A. Pandey and S.C. Tiwari*

Department of Forestry, Wildlife and Environmental Sciences, Guru Ghasidas Vishwavidyalaya, Bilaspur, Chhattisgarh, 495009, India

*Corresponding Author:
S.C. Tiwari
Department of Forestry, Wildlife and Environmental Sciences, Guru Ghasidas Vishwavidyalaya, Bilaspur, Chhattisgarh, 495009, India
E-mail: ankitforestry21@gmail.com
Date of Received 04 October 2023
Date of Revision 17 May 2024
Date of Accepted 26 August 2024
Indian J Pharm Sci 2024;86(4):1176-1186  

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Abstract

Chrysopogan zizaniodes is the well-known eco-friendly plant known for the essential oil obtained from its roots. It is the most popular essential oil which does not have any synthetic substitute available. The essential oil of vetiver is widely utilized in traditional Thai, Chinese, and Ayurvedic medicine to cure a variety of illnesses. The essential oils with various biological properties are employed in the culinary, pharmaceutical, food and beverage and cosmetic industries. The current study is the review of chemical makeup, oil quality (as per Bureau of Indian Standards) as well as the bioactivities the of the vetiver essential oil. Various pharmacological studies have found that vetiver oil has significant effects as an antifungal, antibacterial, antioxidant, anti-inflammatory, and cytotoxic agent against cancer, as well as being beneficial in aromatherapy. The essential oil used in conventional medicine to cure a variety of illnesses, such as mouth ulcers, fever, headaches, depression, nervous tension, anxiety disorders, insomnia, and sexual dysfunction. Root is used as alexiteric, stomachic, carminative, astringent, and boosts the immune system in addition to treating skin conditions, urinary problems, jaundice, and flatulence as well as anaemia, and haemoptysis.

Keywords

Aromatic plant, essential oil, herbal medicine, vetiver

Essential Oils (EOs) do not need an introduction because they are highly regarded as plantbased products with enormous therapeutic and economic potential. They are obtained from various plant parts such as flowers, buds, stems, leaves, fruits, seeds, and roots, to name a few[1]. Medicinal and aromatic plants are among the most important types of horticulture crops that play a special role in sustaining various pharmaceutical, perfumery, and cosmetic industries in India and abroad[2-4]. The root is the most economically important part of the vetiver plant[5]. Vetiver, botanically known as Chrysopogon zizanioides (C. zizanioides) (L.) Roberty Syn., Vetiveria zizanioides (V. zizanioides) Nash is a perennial herbaceous grass belonging to the Poaceae family. It is commonly known as Khus or Khas-Khas[6,7]. Its origin is India, and it grows wildly in most parts of the world, from tropical to Mediterranean climates, including regions in Asia, Central and South America, Oceania, and Africa[8-10]. It is grown for its exceptional ability to create an EO, a complex blend of sesquiterpene alcohols and hydrocarbons[11,12]. Due to its distinctive aroma, which is not produced by any synthetic chemical, vetiver oil is also known as the "oil of tranquility"[11-14]. The largest producers of vetiver EO in the international market are Indonesia, Haiti, Brazil, China, India and Guatemala[10,15-17]. The major consumers of vetiver oil are the United States, Europe, India, and Japan[1,18]. In India, vetiver is mostly grown in the southern and peninsular regions, including Uttar Pradesh, Rajasthan, Bihar, Kerala, Tamil Nadu, Karnataka, and other states. There are two strains, South Indian and North Indian, with several vernacular names[1,4,19,20]. India produces only 20-25 tonnes of vetiver EO annually, compared to the estimated 600-700 tonnes produced worldwide. The estimated cultivation area for vetiver has reached nearly 10 000 hectares[10,21]. Vetiver grass is grown for the extraction of an EO with significant commercial value, used in fragrance and aromatherapy[22,23]. It is mostly employed in high-end perfumery, where its odor persistence makes it valuable as a fixative when combined with other scents[24,25]. The highly complex chemical makeup of vetiver oil consists primarily of sesquiterpenes and its derivatives, of which vetiverols, their carbonyl compounds, and esters are the primary components. The relative abundance of these chemicals determines the oil's quality. The main odour-influencing components in vetiver oils from various sources are three carbonyl compounds, Alpha (α)-vetivone, Beta (β)-vetivone, and khusimone[2,26]. β-Vetivone has a better odor and is regarded as the most important component, while its major isomer, nordihydro β-vetivone, has a strong, rich, woody-peppery note[19,25]. These numerous active components of vetiver oil provide biological properties like antibacterial, antifungal, antiviral, antioxidant, anti-inflammatory, and anticancer properties[13,15,25]. This review focuses on describing the changes in and availability of the chemical composition of vetiver oil from different geographic regions, the quality of the oil, and its uses in various pharmaceutical (bioactivity) and medicinal capabilities of vetiver EOs.

Methods

An extensive search of scientific databases including the Web of Science, Google Scholar, Scopus, ISC, and PubMed was used in this review to gather evidence on vetiver's chemical composition and phytochemical qualities. The keywords used in the database for the literature survey were chemical composition of vetiver, vetiver oil quality, pharmacological uses of vetiver, chemistry of vetiver oil, and bioactivity. The literature in this study has included original research papers, review papers, as well as a few books on herbal and traditional medicines.

EO Extraction

EOs produced from different herbs and aromatic plants have seen an increase in popularity in recent years. Hydro distillation (traditional method), steam distillation, solvent extraction, microwave assisted extraction, supercritical fluid extraction and CO2 expanded ethanol method are the current vetiver oil extraction techniques[14,17,27,28]. In order to obtain the EOs from medicinal herbs and plants, hydro distillation has been the most popular technique among the various methods of oil extraction[17]. The EO obtained from various extraction methods shows significant differences in yield percentage, chemical composition, extraction time, and other biological activities of vetiver oil, as presented in Table 1. Pripdeevech et al.[29] reported that there was no discernible difference between the composition of vetiver oil obtained using the steam distillation and solvent extraction apparatus.

Parameter Methods of oil extraction
HD CXE SFE
Yield (%) 0.6 5.12 0.5
Oil colour Pale yellow Light yellow Greenish brown
Time of extraction (h.) 12 3 2
Chemical composition      
Hydrocarbon 90.71 64.46 81.91
Alcohol 2.77 - -
Carbonyl compound - 5.42 -
Carboxylic acid 2.66 - -
Total identified (%) 96.14 69.88 81.91

Table 1: General Comparison of Vetiver Oil Obtained from different Extraction Methods.

Chemical Composition of Vetiver EO

Numerous studies have been conducted on vetiver oil chemical makeup. Over 300 chemicals have been identified, with sesquiterpenes and their derivatives like alcohols, hydrocarbons, and ketones dominating the majority of them[30]. The oil produced by vetiver grown in regular soil had 37 volatiles, according to analysis. Pripdeevech et al.[29] studied vetiver cultivation using different methods and found that 39 volatile components were present in the oil extracted from vetiver grown in normal soil with microorganisms. The major component was (Z)-9,10-dehydro-2-norzizaene, comprising 46.03 % of the oil. The oil produced by vetiver grown in normal soil had 37 volatiles, the three main ones among these were (Z)-9,10- dehydro-2-norzizaene (20.78 %), khusimone (20.57 %), and khusimol (11.11 %). Champagnat et al.[30] reported that the EOs of V. zizanioides Nash from 9 nations-Brazil, China, Haiti, India, Java, Madagascar, Mexico, Reunion, and Salvador have different chemical compositions. About 110 components, mostly sesquiterpenes, were found in oils after analyses using Gas Chromatography-Mass Spectrometry (GC-MS). After the GC-MS analysis of vetiver oil, Hammam et al.[31] found that the 15 different compounds shows that sesquiterpenes are the most common class of chemicals. The most crucial ingredients were alcohols and acids. The main compounds among the alcohols in vetiver oil include preziza-7(15)-en-12-ol, cedren-5-en- 15-ol, preziza-7(15)-en-3-ol, ziza-6(13)-en-12-ol (khusirnol), ziza-5-en-12-ol, 12-nor-ziza-6(13)- en-2-ol, and khusian-2-ol (helifolan-ol). Similarly, Oliveira et al.[13] and Lunz et al.[7] reported that there were 22 different compounds were found, the majority of which (70.4 %±0.1 %) are oxygenated sesquiterpenes. The primary ingredients in vetiver EO were khusimol (30.0 %±0.3 %), eudesmol (10.8 %±0.3 %), muurolene (6.0 %±0.1 %), and patchouli alcohol (5.6 %±0.2 %). The Srilanka ecotype of vetiver from Northeast Thailand was steam-distilled to produce a viscous light-brown oil with a balsamic, earthy, and sweet woody scent that contained between 0.3 and 1.0 % volume by weight. The main components were khusimol (12.7 %), longipinene (4.2 %), valerenol (3.9 %), and epizizanal (3.3 %), with α-vetivone and β-vetivone following closely behind (2.0 % and 1.6 %, respectively)[32]. Similary Lima et al.[33] found that after the GC-MS analysis revealed a variety of substances, including khusimol (19.57 %), (E)-isovalencenol (13.24 %), α-vetivone (5.25 %), vetiselinenol (5.08 %), α-cadinol (5.01 %), α-vetivone (4.87 %), and hydroxy-valencene (4.64 %) being the main substances in the EO. The chemical composition of C. zizanioides EO with number of compounds has been found, compiled from the different geographic location of the world is shown in Table 2.

S. No. Location Chemical composition Total no. of compound References
1. China 2,3,5,5,8,8-Hexamethyl-cycloocta-1,3,6-triene, 1,5,9,9-Tetramethyl-2-methylene-spiro[3.5]non-5-ene, (+)-Sativen, 4,8,8-Trimethyl-2-methylene-4-vinylbicyclo [5.2.0]nonane, a-Amorphene, 2-Isopropenyl-1,3,5-trimethylbenzene, a-Gurjunene, b-Vatirenene, 9 d-Cadinene, b-Guaiene, Dehydro-aromadendrene, Cubenol, (+)-Ledene, Epiglobulol, Widdrol, 6-Isopropenyl-4,8a-dimethyl-1,2,3,5,6,7,8,8a-Octahydro-naphthalen-2-ol, 3-(2-Isopropyl-5-methylphenyl)-2- methylpropionic acid, Cedr-8-en-13-ol, Ethyl 4-(4-methylphenyl)-4-pentenoate, Isovellerdiol, a-Curcumene, 3,3,8,8-Tetramethyl-tricyclo[5.1.0.0(2,4)] oct-5-ene-5-propanoic acid, Solavetivone, 3,8-Dimethyl-4-(1-methylethylidene)- 2,4,6,7,8,8a-Hexahydro-5(1H)-azulenone, (-)-Spathulenol. 25 [11]
2. Turkey 8,9-dehydro-cycloisolongifolene, cadina-1(10),4-diene, ar-curcumene, γ-cadinene, β- vetivenene, γ-gurjunene, ledene oxide, η-himachalene, valencene, C15H22O, γ-muurolene, β-guaiene, allaromadendrene oxide, δ-cadinol, junipene, tau-muurolol, trans-caryophyllene, cubenol, caryophyllene oxide, khusinol, 8-cedren-13-ol, C13H18O, β-gurjunene, thujopsene-13, dehydro-aromadendrene, β-vetivone, α-vetivone. 30 [26]
3. Comoros α-Phellandrene, (E)-Isoeugenol, Khusimene, ar-Curcumene, α-Amorphene, Valencene, g-Vetivenene, Elemol, b-Vetivenene, b-calacorene, Spathulenol, trans-Sesquisabinene hydrate, Khusimone, 1,10-epi-cubenol, 10-epi-g-Eudesmol, 1-epi-cubenol, epi-α-Cadinol, α -Cadinol, 7-epi-α-Eudesmol, Valerianol, epi-Zizanone, Khusinol, Khusian-2-ol, Zizanal, (Z)-β-Santalol, Nootkatol, Juniper camphor, Vetiselinenol, Khusimol, (E)-β-Santalol, 14-Hydroxy-g-cadinene, 13-Hydroxy valencene, Bicyclo- vetivenol, Isovalencenol, Nootaktone, b-Vetivone, Khusinol acetate, (Z)-β-Santalol acetate, a-Vetivone, Epi-Laurenene. 41 [34]
4. Brazil Naphthalene, β-cubebene, Isolongifolene, β-Gurjunene, α-Patchoulene, β-Cadinene, α-Muurolene, α-Amorphene, Valencene, α-Bulnesene, α-Elemol, β-Vatirenene, β-Eudesmol, Spathulenol, Guaiol, Humulane-1,6-dien-3-ol, Cubenol, Agarospirol, Cedren-13-ol, Patchouli alcohol, Khusimol, Nootkatone, 22 [13]
5. India Cycloisolongifolene, All-oaromadendrene, Alpha -copaene, gamma-Muurolene, Germacrene D, Guaia-6,9-diene, Isolongifolol, Isospathulenol, Isoledene, Epiglobulol, Tau.-Muurolol, Cubenol, Isoaromadendrene epoxide, Globulol, Humulane-1,6-dien-3-ol, Caryophyllene, Aristolene, Alpha-Ylangene, 2(1H) Naphthalenone, 3,5,6,7,8,8a- hexahydro-4,8adimethyl- 6-(1- methylethenyl)-, beta-Vatirenene, Alpha - Cedrene, Selin-6-en-4α-ol, Gamma-himachalene, Valerenol, Alpha -Guaiene, Alpha - Gurjunene, Longiverbenone, Alpha -Longipinene, Alpha -Amorphene, bete-Copaene, Nootkatone, Isolongifolene, 4,5dehydro. 32 [18]
6. Thailand Tricyclene, Camphene, Camphor, Bornyl acetate, Silphiperfol-5-ene<7-epi->, Presilphiperfol-7-ene, Silphiperfol-5-ene, Silphiperfol-4,7(14)-diene, Silphiperfol-6-ene, Cadina-1(10), 6,8-triene, Cedrene<beta->, Caryophyllene(E-), Copaene<beta->, 9-Methyl-S-octahydroanthracene, Humulene<alpha->, Cadina-1(6), 4-diene<cis->, Neocallitropsene<alpha->. Cuparene, 3-Methyl-2-pent-2-enyl-cyclopent-2-enone, Cameroonan-7-alpha-ol, Humulane-1,6-dien-3-ol, Silphiperfolan-6-beta-ol , Guaia-3,9-diene, Prenopsan-8-ol, Caryophyllene oxide, Alloaromadendrene oxide-(2), Humulene epoxide II, Humulene<beta->, Silphiperfol-6-en-5-one, Acorenol<alpha->, Vatirenene<beta->, Bisabolol<epi-beta->, Himachal-4-en-1-beta-ol<11-alphaH->, 1,4-Methanoazulen-7(1H)-one, octahydro-4,8,8,9-tetramethyl-, (+)- 34 [35]
7. Taiwan 2,3,5,5,8,8-Hexamethyl-cycloocta-1,3,6-triene, 1,5,9,9-Tetramethyl-2-methylene-spiro[3.5]non-5-ene, (+)-Sativen, 4,8,8-Trimethyl-2-methylene-4 vinylbicyclo[5.2.0]nonane, ?-Amorphene, 2-Isopropenyl-1,3,5-trimethylbenzene, ?-Gurjunene, ?-Vatirenene, ?-Cadinene, ?-Guaiene, Dehydroaromadendrene, Cubenol, (+)-Ledene. Epiglobulol, Widdrol, 6-Isopropenyl-4,8a-dimethyl-1,2,3,5,6,7,8,8a-octahydro-naphthalen-2-ol, 3-(2-Isopropyl-5-methylphenyl)-2-methylpropionic acid, Cedr-8-en-13-ol,
Ethyl 4-(4-methylphenyl)-4-pentenoate,
Isovellerdiol, ?-Curcumene, 3,3,8,8-Tetramethyl-tricyclo [5.1.0.0(2,4)] oct-5-ene-5-propanoic acid, Solavetivone, 3,8-Dimethyl-4-(1-methylethylidene)-2,4,6,7,8,8a-hexahydro-5(1H)-azulenone, (−)-Spathulenol,
25 [23]
8. Egypt Linaloo, Trans-Rose oxide, Menthone, Trans Methone, Citronellol, D-Carvone, Geraniol, Citronellyl formate, Geranyl formate, Zizanal, Beta-Bourbonene, Acora-3(7),14-diene, Caryophyllene, Daucene, (+)-Epi-bicyclosesquiphellandrene, Prezizaene, Khusimene, Alpha. Gurjunene, (1R,5R)-1-Iso propyl-8-methyl-4- methy lenespiro [4.5] dec-7-ene, Selina-3,7(11)-diene, α-Amorphene, Cis-Eudesma-6,11-diene, Beta-Vetispirene, Beta-Cadinene, Gamma-Muurolene, D-Cadinene, Iso ledene, Cadina-1(10),4-diene D-Amorphene, 11,12,13-tris-nor -trans-Eud esm-5-en-, 7-one, Alpha-Calacorene, β-Vatirenene, Isolongifolene, 4,5,9,10-dehydro-, 4-(1,3,3-Trimethyl-bicyclo. [4.1.0] he pt-2-yl)-but-3-en-2- one, γ-Vetivenene, Ylangene, Beta-Maaliene, 13-nor-Erem ophil-1(10)-en-11-one, Junenol, γ-selinene, Beta-Cadinene, Valencene, Beta-Guaiene, 2-Isopropyl-5-methyl-9-methylene-bicyclo-1-decene (4.4.0), Cyclocopacamphenol, Spiro [4.5] dec -8-en-7-ol, 4, 8- dimethyl-1-(1-methy lethyl)-, Zizanol, Khusiol, Juniper camphor, Cycloheptane, 4-methylene-1-methyl-2- (2-methyl-1-propen-1-yl)-1-vinyl-, Delta-selinene, Vetiselinenol, α-Isonootkatol, Khusimol, α-Vetivol, α-Costol, Valerenol, β-Vetivenene, (E)-Eremophila-1(10),7(11)-dien-12-ol (Isoval encenol), (Z)-Isovalencenal, β-Vetivone, (E)-Isovalencenal [eremophila-1(10),7 (11)-di en-12-al, α-vetivone. 63 [36]
9. Indonesia Khusimol (zizanol), Vetiselinenol (isonootkatol), Cyclocopacamphan-12-ol (epimer A), α-Cadinol, α-Vetivone (isonootkatone), β-Vetivenene, β-Eudesmol, β-Vetivone, Khusenic acid, β-Vetispirene, γ-Vetivenene, α-Amorphene, (E)-Eudesm-4(15),7- dien-12-ol, b-Calacorene, g-Cadinene, (Z)-Eudesm-6-en-11-ol, g-Amorphene, Ziza-5-en-12-ol, b-Selinene, (Z)-Eudesma-6,11-diene, Salvial-4(14)-en-1-one, Khusinol.
Cyclocopacamphan-12-ol (epimer B), Selina-6-en-4-ol, Khusian-ol, d-Amorphene, 1-epi-Cubenol, Khusimene (ziza-6(13)- ene), Ziza-6(13)-en-3b-ol, Ziza-6(13)-en-3-one, 2-epi-Ziza-6(13)-en-3a-ol, 12-Nor-ziza-6(13)-en-2bol, a-Vetispirene, Eremophila-1(10),7(11)- diene, Dimethyl-6,7-bicyclo- [4.4.0]-deca-10-en-one, 10-epi-g-Eudesmol, a-Calacorene, (E)-Opposita4(15),7(11)-dien12-ol, Prekhusenic acid, 13-Nor-eudesma-4,6-dien-11-one, Isovalencenol, Spirovetiva-1(10),7(11)- diene, 2-epi-Ziza-6(13)-en-12-al, (E)-Isovalencenal, Preziza-7(15)-ene, (Z)-Eudesma-6,11-dien3b-ol, Intermedeol (eudesm-11- en-4-ol), Isoeugenol, Isokhusenic acid, Elemol, Eremophila-1(10),6-dien12-al, Juniper camphor, Khusimone, Eremophila-1(10),4(15)- dien-2a-ol, Eremophila-1(10),7(11)- dien-2b-ol, (Z)-Isovalencenal, allo-Khusiol, Methyl-(E)-eremophila1(10),7(11)-dien-12-ether, (E)-2-Nor-zizaene, (Z)-Eudesm-6-en-12-al, Funebran-15-al.
61 [37]

Table 2: Chemical Composition of Vetiver Grass from the Different Location of World Studied by Various Researchers

An EOs aroma and chemical makeup can differ depending on the region, climate, and growing conditions (such as soil type, altitude, and water availability), the season (such as before or after the flowering period), and even the time of day when it is harvested[1,15,25]. After studying the vetiver oil composition from various countries, as shown in Table 2, it was found that the highest number of compounds were present in Egypt, followed by Indonesia, while the lowest number of compounds were found in Turkey, with only 22 compounds. India has two recognised vetiver varieties: The Bharatpur or North Indian type is primarily found in the Indian states of Rajasthan, Madhya Pradesh, Uttar Pradesh, and Bihar. It has abundant flowering, high seed setting, narrow leaves, and vigorous roots that produce laevorotatory root oil (khush oil) with a low concentration and superior quality. The South Indian cultivated variety can be found in the states of Andhra Pradesh, Karnataka, Tamil Nadu, and Kerala along the East and West coastlines of the Indian peninsula[1,7]. Chahal et al.[1] conducted a study on Indian vetiver oil and reported that a total of 29 and 33 compounds in South and North Indian vetiver oils, respectively. The chemical composition of North Indian and South Indian strains of vetiver presented in Table 3.

S. No Component Concentration percent
North India South India
1 β-caryophyllene - 0.37
2 Sativen 0.65 -
3 Khusimene 0.66 1.59
4 α-Humulene - 0.03
5 α-Amorphene 0.22 1.68
6 α-Bisabolol 0.19 -
7 γ-Cadinene 0.82 -
8 β-Caryophyllene oxide 0.28 -
9 Allo-aromadendrene 0.17 -
10 Cubenol 1.64 -
11 δ-Guaiene - 1.42
12 Valencene - 1.31
13 β-Vetivenene - 0.14
14 β-Vatirenene - 0.72
15 Caryophyllenyl alcohol - 2.3
16 Humulane-1,6-dien-3-ol 0.87 1.42
17 10-epi-gamma-eudesmol 0.46 -
18 β-lonol 0.46 -
19 β-Bisabolol 0.57 1
20 Epiglubulol 1.95 -
21 Selina-6-en-4ol - 2.11
22 Globulol - 1.91
23 Junipene 5.54 1.6
24 α-Cadinol 1.46 1.74
25 Guaiol 1.03 1.58
26 α-Eudesmol 0.49 -
27 β-Eudesmol 0.97 1.28
28 Allo-aromadendren oxide - 0.83
29 β-Cedren-9-α-ol 1.76 -
30 Farnesol 2.65 -
31 Khusinol 10.28 -
32 γ-Muurolene 4.56 -
33 E-Caryophyllene 0.74 -
34 γ-Cadinene aldehyde 1.28 -
35 Patchouli alcohol - 1.61
36 γ-Gurjunepoxide - 1.14
37 Cyclosativene - 2.06
38 Cedryl acetate - 0.29
39 Spathulene 1.28 2.37
40 γ-Maaline 1.57 -
41 Calerene 1.57 -
41 γ-Himachalene 0.23 -
42 Viridiflorene - 4.64
43 Khusimol 16.25 15.77
44 Bicyclovetivenol 2.88 10.76
45 α-Vetivone 2.01 3.04
46 Velerenol - -3.44
47 Germacrene-D 9.73 -
48 Cedrene-13-ol-8 2.23 1.05
  Total 33 29

Table 3: Chemical Composition of North and South Indian Strains of Vetiver

The antipodal sesquiterpenes of the cadinane class are abundant in North Indian vetiver, while the α and β-vetivones are lacking. The dextrorotation of the south Indian vetiver root oil is visible. It contains the same sesquiterpene ketones, such as vetivones, vetispirenes, eudesmane, and zizaane sesquiterpenes that are present in vetiver root oils produced in other countries[16]. Mallavarapu et al.[16] found that 80 components have been identified, accounting for 94.5 %-97.8 % of the oils. Sesquiterpenes, oxygenated sesquiterpenes, and oxygenated sesquiterpenes with cedrane, bisabolane, eudesmane, eremophilane, and zizaane skeletons were abundant in the oils from Bangalore, Hyderabad, Kundapur, and Mettupalayam[34-38].

Physico-Chemical Properties of Vetiver EO

Physico-chemical characteristics of the oil, including an assessment of its aroma, were used to determine its quality. The presence of several ketonic sesquiterpenes, including vetiverol, α-vetivone, and β-vetivone, as well as the ester vetiveryl vetivenate, gives vetiver oil its distinctive aroma. The fixative activity of oil is aided by sesquiterpene alcohols such as vetivol acetate and vetiverol. In a study by Kadarohman et al.[39] vetiver EO quality was observed from organic and non-organic vetiver plants and found that compared to oil obtained from inorganic cultivation, organic was higher in quality. In terms of appearance, organic vetiver oil was more concentrated and had no black spots. Chemically, vetiver EO from organic cultivation includes more vetiverol and less pesticide residue[40]. The quality of vetiver oil from different geographic locations as compared to Bureau of Indian Standards (BIS) and Karnataka Soaps and Detergents Limited (KSDL) value has been presented in Table 4.

S.No. Parameter BIS Value KSDL value Putrawan et al.[40] Kadarohman et al.[39] Dubey et al.[38] Khalil et al.[41] Yanto et al.[2]
1       Colour Brown to reddish viscous liquid Brown to reddish viscous liquid Pale yellow to reddish brown Yellow to reddish brown Brown to yellowish brown clear liquid - Reddish brown
2      Specific gravity 0.9926-1.0444 0.985-1.020 0.980-1.003 0.980-1.003 1.0118-1.0026 1.002 1.0097
3        Refractive index@24° 1.588-1.5306 1.5132-1.5242 1.52-1.53 @20° 1.520-1.530 1.5147-1.5220 1.5112 1.5308
4        Optical Rotation   +15° to +35°   - -57.70 to +28.23 +40.0 -
5        Acid value 8.4-40.1 35 10-35 - 21.30-28.45 46 11.5
6        Ester value 5.6-24.6 5-16 -- 5-26 8.36-11.27 14 18.57
7        Saponification value - - - - -- 60 -
8        Odour Rosy odour Woody aroma Vetiver characteristics   Heavy earthy, green to heavy woody - Slightly smoky

Table 4: Physico-Chemical Properties of Vetiver Oil

Bioactivity of Vetiver EO

Antimicrobial activity:

The vetiver EO had excellent antibacterial efficacy against all of the clinical pathogens that were tested, with no discernible difference in susceptibility between gram-positive and gram-negative bacteria[41-43]. By measuring the zone of inhibition, ethanolic root extract of V. zizanioides is shown to have antibacterial activity. The ethanolic root extracts exhibit antimicrobial properties due to presence of flavonoids, terpenoids, and tannins included in vetiver[44]. Sangeetha et al.[45] obtained similar findings and found that vetiver leaf extract had the highest mean zone of inhibition against Staphylococcus aureus. Soni et al.[46] studied that vetiver solvent extracts have the potential to be utilised as an antimicrobial medication against infectious agents and as a treatment for a variety of infectious disorders. According to the Efe et al.[43] findings, vetiver EO showed an inhibitory impact against the tested microorganisms that was greater than or comparable to that of at high vetiver EO concentrations.. In a study conducted by Nantachit et al.[47] found that the root of the Surat Thani cultivar of C. zizanoides (L.) showed antimicrobial activity due to presence of vetiverin compound in oil. Jayashree et al.[48] reported that the root extracts of vetiver showed maximum zones of inhibition of 30 mm against Staphylococcus aureus and 33 mm against Candida albicans, while the lowest zones of inhibition were 24 mm against Escherichia coli (E. coli) and 28 mm against Cryptococcus neoformans, respectively.

Antibacterial activity:

Numerous studies have revealed that vetiver EO has antibacterial properties that can combat a variety of bacterial strains, including Staphylococcus aureus, Streptococcus pyogenes, E. coli, Corynebacterium ovis, Mycobacterium smegmatis, Acinetobacter baumannii, Aeromonas veronii, Klebsiella pneumoniae, Pseudomonas aeruginosa[49,1,50,43]. Nantachit et al.[47] and Pawar et al.[50] found that crude root extract from the Surat Thani cultivar of V. zizanioides (L.) Nash exhibited antibacterial efficacy against four pathogenic microorganisms. The EO of C. zizanioides contains alkaloids, terpenoids, flavonoids, saponins, phenols, and tannins that, either singly or in combination, have antibacterial characteristics[51]. Putiyanan et al.[52] showed that C. zizanioides (L.) has antibacterial action against Pseudomonas aeruginosa, E. coli, and Staphylococcus aereus. conducted an investigation and proposed that Cedr-8-en-13- ol, 6-isopropenyl-4, 8a-dimethyl-1,2,3,5,6,7,8,8a-octahydro-naphthalen-2-ol, Delta (δ)- Selinene, Gamma (γ)-Gurjunenepoxide-(2), and solavetivone are the most important compounds in the antibacterial activity of vetiver oil against the Multidrug Resistance (MDR) bacteria models used in their study.

In a study Efe[25] found that the vetiver EO had strong antibacterial activity for Enterobacter cloacae, Enterococcus faecalis, E. coli, and Proteus vulgaris in the Minimum Inhibitory Concentration (MIC) values, 15.63, 31.25, 15.63, and 15.63 g/ml, respectively. Similarly, Oliveira et al.[13] found that when tested against Prevotella nigrescens, Fusobacterium nucleatum, Prevotella melaninogenica, and Aggregatibacter actinomycetemcomitans, vetiver oil exhibited strong antibacterial activity, with MIC values ranging from 22-62.5 μg/ml and Minimum Bactericidal Concentration (MBC) values ranging from 22-400 μg/ml.

Antioxidant activity:

Vetiver oil showed antioxidant activity and has applications in both fragrance and medicine. Two separate in vitro assays, the 1,1-Diphenyl-2- picrylhydrazyl (DPPH) free radical scavenging assay and the Fe2+ metal chelating assay, were used to assess the antioxidant capabilities of vetiver oil[50-54]. Many studies have shown the biological activity of the EO of V. zizanioides roots. Kim et al.[55] found that the antioxidant property of vetiver has been identified by three distinct compounds vetivenene, both β-vetivone and α-vetivone. The ethanolic extract of vetiver root is used for various antioxidant activities, lowering oxidation ability, superoxide anion radical capturing ability, and overall antioxidant capacity[44]. Subhadra et al.[49] had conducted research and found that V. zizanioides scavenges free radicals, reducing the harm caused by oxidative stress in many illness states, and acting as a possible natural source of antioxidant. Similarly, in a study Samman et al.[36] concluded that the overall antioxidant capacity of the vetiver EO was 75.5 % at 0.1 mg/ml (100 ppm), and the total phenolic content was 6.7 mg Gallic Acid Equivalents/g.

The antioxidant activity of EO is depending upon their chemical composition particularly the presence of compound which have radicle function. Soidrou et al.[34] reported that antioxidant action is dosage dependant and found that the concentration of 0.5 mg/ml was highest concentration which shows the strong activity (60.43 %). The concentration of 0.03125 mg/ml, the lowest concentration tested, showed the lowest antioxidant activity, 52.74 %.

Anti-inflammatory activity:

The action that relieves pain is anti-inflammatory. Vetiver EO had an anti-inflammatory activity. It is mostly utilised as an anti-inflammatory in the neurological and circulatory systems. It is also effective for treating inflammations caused by sunburn, dehydration, and dry winds[56,44]. Chou et al.[11] found that 25 compounds that make up V. zizanioides-EO, with cedr-8-en-13-ol (12.4 %), α-amorphene (7.80 %), β-vatirenene (5.94 %), and α-gurjunene (5.91 %) being the main constituents. Vetiver EO may suppress the inflammatory responses of Lipopolysaccharide (LPS) -stimulated RAW 264.7 macrophages, including nitric oxide production and cell apoptosis, through the regulation of the expression of the inflammationrelated enzymes Heme Oxygenase-1 (HO-1), inducible Nitric Oxide Synthase (iNOS) and cyclooxygenase-2 and the inflammatory cytokines Tumor Necrosis Factor (TNF)-α, Interleukin (IL)- 1β and Interferons (IFN-β). Lima et al.[33] found that vetiver EO can stop abdominal writhes, reduce the second phase of formalin-induced pain, and inhibit carrageenan-induced inflammation, providing evidence of its analgesic and anti-inflammatory properties.

Anti-cancer activity:

Vetiver EO is cytotoxic to cancer cells[37]. Chen et al.[57] conducted research and found that vetiver oil reduced the development of SiHa cervical cells by 89 %, CaSki cervical cells by 88 %, and MCF- 7 breast cancer cells by 89 %. Similar results were found by Hanifa et al.[58] that the substances found in vetiver oil principally responsible for the cytotoxic actions are β-caryophyllene and α-humulene, which especially influence Triple Negative Breast Cancer (TNBC) directed at cannabinoid receptor 2. South Indian vetiver grown for commercial purposes contained 0.37 % β-caryophyllene (Table 2). Additionally, β-caryophyllene has received a lot of attention as a potential cancer treatment and prevention agent[58]. Sinha et al.[59] reported that in human lymphocytes, vetiver acetate was found to be considerably genotoxic and cytotoxic at high doses, but vetiver oil is safe for consumption at moderate quantities.

In a study Chitra et al.[60] found that the root extract of vetiver showed cytotoxicity when applied to a cancer cell line. The result reveals that the human breast cancer MCF-7 cell line has an half maximal Inhibitory Concentration (IC50) concentration ranging from 5-50 g/ml. MIC was seen between 31 and 37 g/ml.

Anti-fungal activity:

Phytopathogenic fungi were examined for resistance to the antifungal effects of sesquiterpenoids of vetiver oil[42,50,1]. The antifungal action of vetiver has also been demonstrated in numerous investigations against Alternaria alternate, Fusarium oxysporium[50], Rhizoctonia bataticola, Sclerotium rolfsii, Aspergillus niger, Candida albicans, and Cryptococcus neoformans[37,43]. Khusinodiol monobrosylate, one of the several substances examined, has been found to be an efficient antifungal agent against fungi[1]. Putiyanan et al.[52] found that six different species of vetiver have been found to have antifungal activity against Trichophyton mentagrophytes. Dubey et al.[38] studied that antifungal activity against the phytopathogenic fungus Rhizoctonia solani, 50 % Effective Dose (ED50) (μg/ml) showed that South Indian vetiver oil was substantially more effective than North Indian oil. Similarly, Samman et al.[36] conducted a study and found that vetiver oil showed a considerable inhibition in radial growth of all the studied fungus species, including Fusarium oxysporum, Alternaria citri, and Rhizoctonia solani at the lowest application rate (500 g/ml), and it was strengthened when concentration was raised to (1000 g/ml). In a Study by Power et al.[61] revealed that EOs from vetiver shown significant antifungal activity against C. neoformans (MIC=20 g/mL) and cytotoxic action against MCF-7 cells (IC50=23.9 g/mL). Sesquiterpene alcohols and khusimol are abundant in vetiver EO. The development of A. niger and C. albicans was inhibited by vetiver oil (MIC=78 and 313 g/ml).

Conclusion

The EO of C. zizanioides shows promise for usage in novel care products and that it can be further used to develop new medications, cosmetic and various industrial products. The complexity of the oils' chemical makeup and the variety of their constituents and chemical structures are responsible for the wide range of biological activities. It can be concluded that vetiver oil has been shown effectiveness against bacterial, fungal, microbial, cancer diseases with great economic importance. It is also a complex mixture of various sesquiterpenes, hydrocarbons, flavonoids, saponins, phenols, and tannins, and is used in various medical and cosmetic industries.

Furthermore, as biological activity can strongly vary depending on a species chemical makeup inside it, future research should concentrate on plant culture and EO standardisation. Various chemical compounds of vetiver are still unidentified and needs to identify their properties and uses in various pharmacological activities.

Acknowledgement:

Authors acknowledged the support received from the central library staff members, Guru Ghasidas University) for the literature search.

Authors' Contributions:

Ankit Pandey: Data curation, data analysis, drafting, writing, and formatting. S.C. Tiwari: Conceptualization, draft correction and editing, and suggestions for improvements.

Conflict of interests:

The authors declared no conflict of interests.

References