Volatile Chemical Composition Research Articles

Variations in Volatile Oil Yield and Composition of "Xin-yi" (Magnolia biondii Pamp. Flower Buds) at Different Growth Stages.

Dried flower buds of Magnolia biondii Pamp. are the main ingredient in "Xin-yi" in China, and the volatile oils of M. biondii flower buds are the principal medicinal component. Gas chromatographymass spectrometry (GC-MS) and microscopic techniques were employed to detect the volatile yields of M. biondii flowers at various growth stages. The volatile oil yields of M. biondii flowers differed significantly at different growth stages and were closely related to flower dry weight, oil cell density and degree of oil accumulation. In February 2016, flower buds had the highest dry weight, the maximum percentage of oil cells at the oil saturation stage and the highest density of oil cells, which coincided with the highest oil yield. In March 2016, flower buds had a lower dry weight, a higher percentage of oil cells at the oil-degrading stage and the lowest oil cell density, resulting in decreased oil yields. The total amounts of the major medicinal components in the M. biondii flower also showed regular changes at different growth stages. In January and February of 2016, M. biondii flowers had a higher dry weight, volatile oil yield and total content of medicinal ingredients, which was the best time for harvesting high-quality medicinal components. Our study reveals that volatile oil content and chemical composition are closely related to the growth stage of M. biondii flower buds. The results provide a scientific morphology and composition index for evaluating the medicinal value and harvesting of high-quality M. biondii medicinal herbs.

Determinants of the Sensory Quality of Półgęsek in Relation to Volatile Compounds and Chemical Composition

1. Anandh M.A., Lakshmanan V., Storage stability of smoked buffalo rumen meat product treated with ginger extract. J. Food Sci. Technol., 2014, 51, 1191–1196. Google Scholar

Volatile organic compounds of Acacia longifolia and their effects on germination and early growth of species from invaded habitats

ABSTRACTAcacia longifolia, a highly invasive species that invades coastal ecosystems in Mediterranean areas, produces significant impacts at different scales. Abundant foliage and thick canopies create a dense atmosphere that led us to hypothesise that the release of volatile organic compounds (VOCs) could play a role in the reduction of biodiversity observed in invaded areas. Therefore, we suggested that VOCs emitted by A. longifolia could exert inhibitory effects on physiological and biochemical parameters of native species. Using glass chamber bioassays, we evaluated the effect of aerial contact between VOCs from different plant parts of A. longifolia material and some native species. Volatile chemical composition was further analysed using GC-MS. Our results indicated that VOCs produced a notably reduction of seed germination. Furthermore, volatiles from leaves and flowers significantly decreased root length, shoot length and biomass for all species. Proline and malondialdehyde content did not significantly increase after contact with VOCs. Finally, chemical profile of VOCs from flowers, leaves and litter was significantly different, both qualitatively and quantitatively. As far as we know, our results constitute the first evidence of phytotoxicity induced by VOCs from A. longifolia, suggesting that flowers and leaves could influence its surrounding environment through VOCs release.

Volatile essential oil chemical composition of basil (Ocimum basilicum L. ‘Green’) cultivated in a greenhouse and micropropagated on a culture medium containing copper sulfate

The objective of this study was to determine the effects of copper sulfate (CuSO4) on the chemical composition of basil (Ocimum basilicum L. ‘Green’) using static headspace extraction. The basil was cultivated in vitro and ex vitro. The sowing was completed in trays, and the seedlings were transplanted to pots and grown in a protected environment for 180 d. For in vitro cultivation, the seeds were placed on Murashige and Skoog (MS) medium enriched with growth regulators, sucrose, agar, and CuSO4 (at 0 μM [control], 25 μM, or 75 μM). Volatile organic compounds emitted from the excised leaves were collected by the static headspace technique, and identified by gas chromatography coupled to mass spectrometry (GC/MS). Twenty-six compounds were identified in the leaves harvested from the plants cultivated in vitro, while 11 compounds were identified in the leaves sampled from the ex vitro plants. Oxygenated monoterpenes were the main compounds found in plants cultivated ex vitro. Phenylpropanoids predominated in the control and the 25 μM CuSO4 treatments. The main compounds found were methyl eugenol (52.03%) and eugenol (20.66%). For the 75 μM CuSO4 treatment, the major compounds detected were linalool (28.14%) and 1.8-cineole (15.7%). Volatile secondary metabolites of basil cultivated in vitro with CuSO4 were easily isolated and rapidly obtained. The results of this study demonstrate the feasibility and potential of using copper treatments to reduce the impact of seasonality on essential oil production.

Identification of volatile profiles of Rio Red grapefruit at various developmental to maturity stages

Grapefruit is an important citrus crop having unique aroma and flavour. In the current study, the juice quality parameters and volatile chemical composition of grapefruits harvested at five different periods comprising of developmental to maturity stages from June to April were studied. The headspace volatile compounds of grapefruit juice were isolated by solid phase micro-extraction (SPME) using divinylbenzene-carboxen-polydimethylsiloxane (DVB-CAR-PDMS) fibre and identified by gas chromatography-mass spectrometry. The volatiles were separated on WAXPlus capillary column and the results were relatively quantified and expressed as perillyl alcohol equivalents. A total of 25 compounds were identified constituting to nearly 98% of the volatiles. Terpene hydrocarbons accounted for nearly 98% of total volatiles during the various harvest stages. Limonene and β-caryophyllene were found to be most abundant components in all the samples. The levels of limonene (22.3 ± 2.8–5.9 ± 1.4 mg/100 g fresh weight) decreased from June to April, whereas nootkatone was significantly higher in January (19.9 ± 4.1) and April (56.42 ± 6.31 μg/100 fresh weight) as compared to other harvests. Developmental stages and maturity had significant influence on the volatile profile of grapefruit juice.

Deciphering the chemical origin of the semen-like floral scents in three angiosperm plants

The chemical origin and biological role of distinct semen-like odor occasionally found in some flowers are very curious but remain scarcely studied. Here, we used direct ambient corona discharge ionization mass spectrometry (MS) to study the volatile chemical composition behind the semen-like odor emitted by the fresh flowers of Photinia serrulata, Castanopsis sclerophylla and Stemona japonica without any chemical pretreatment. Chemical identification was performed using high-resolution MS analysis in combination with tandem MS analysis and whenever possible was confirmed by the analysis of standard reference compounds. A total of 19 compounds, mostly belonging to nitrogenous volatiles, were identified in P. serrulata, C. sclerophylla, and S. japonica flowers, 1-pyrroline, 1-piperideine, 2-pyrrolidone, and phenethylamine being common in all the three studied species. Several lines of evidence indicate that the major component responsible for the semen-like odor is most likely 1-pyrroline. 1-Pyrroline is most probably formed via the oxidative deamination of putrescine, as indicated by the observation of signal from 4-amino-butanal intermediate. Flower visitation observations suggest that the released volatiles serve to attract dipterans, including Syrphidae, Calliphoridae, and Muscidae. On the analytical side, the comparison of our results to earlier studies also indicate that compared to the traditional GC-MS approach the direct corona discharge ionization mass spectrometry provides more sensitive detection of VOCs with high proton affinity, in particular volatile amines, and therefore can be used to complement traditional GC-MS approach for the highest chemical coverage of VOC analysis.

Secondary Metabolite Profile and Maize Weevil Repellent Activity of the Leaves of Ruta graveolens

Secondary metabolites which make the major contribution to specific odors and flavors of plants play a critical role when dealing as repellents against insects in storage pest management. Thus, identification of those secondary metabolites that have repulsive effect on insect pest behaviors could greatly facilitate the development of green pesticides while ensuring ecological sustainability. Hence, the present phytocentric research study provides the first investigation on volatile profile, chemical composition and repellent potential of the leaves of R. graveolens (Aruda) against the maize weevil, Sitophilus zeamais (Motschulsky) infestations. The volatile organic compound (VOC) profile of fresh leaves of R. graveolens was analyzed with headspace solid-phase microextraction coupled with gas chromatography and mass spectrometry (HS-SPME/GC-MS). Qualitative phytochemical screening of 11 phytoconstituents (alkaloids, saponins, flavonoids, tannins, steroids, terpenoids, anthraquinones, glycosides, phlobatannins, coumarins and phenols) for four leaf extracts (aqueous, n-hexane, ethyl acetate and methanol) was also performed following the standard procedures. In addition, contact and fumigant repellent properties of R. graveolens were also evaluated. A total of 14 compounds representing 99.95% of the total quantum of volatiles were detected in R. graveolens leaves consisting mainly of 2-ketones (93.32%), sesquiterpenoids (1.48%), aliphatic acids and esters (1.29%): 2-Nonanone (25.71%) and 2-Undecanone (55.51%) were the major volatile compounds followed by 2-Decanone (5.60%), 5, 6-diethenyl-1-methyl-cyclohexene (3.76%), 2-Dodecanone (2.74%) and 2-Tridecanone (2.98%). Phytochemical results revealed the absence of phlobatannins and the presence of alkaloids, glycosides and coumarins in each leaf extract. Aqueous leaf extract exhibited the presence for majority of phytoconstituents while hexane demonstrating the least presence. The data on contact and fumigation repellency against S. zeamais indicated strong maize grain protection activities at the highest dosage accounting for 97% and 96% respectively. The present study provides the evidence that R. graveolens leaves contain agriculturally important bioactive secondary plant metabolites, thus justifying the use of plant species with respect to its significant repellent role against S. zeamais populations in post-harvest storage pest management programs. Keywords: Ruta graveolens, Sitophilus zeamais, Secondary metabolites, Repellency, Headspace-solid-phase micro-extraction

Circadian variation and in vitro cytotoxic activity evaluation of volatile compounds from leaves of Piper regnellii (Miq) C. DC. var. regnellii (C. DC.) Yunck (Piperaceae)

Aiming detection of circadian variation in the chemical composition of volatiles from Piper regnellii, the leaves were collected during four different periods (8, 12, 16 and 20 h) in the same day. After extraction by hydrodistillation and GC/MS analysis, no significant variation was observed for the main compounds: germacrene D (45.6 ± 1.5–51.4 ± 3.1%), α–chamigrene (8.9 ± 1.3–11.3 ± 2.7%) and β–caryophyllene (8.2 ± 0.9–9.5 ± 0.3%). Evaluation of in vitro cytotoxicity against several cancer and non-tumourigenic cells indicated promising activity, especially to HeLa (human cervical carcinoma) with IC50 ranging from 11 ± 3 to 17 ± 3 μg/mL. The obtained volatile oils were pooled and subjected to fractionation to afford pure β-caryophyllene, α-chamigrene and germacrene D, being this last compound the more active against HeLa cells with IC50 of 7 ± 1 μg/mL (34 ± 5 μM). Therefore, the predominance of germacrene D in all analysed oils could justify, at least in part, the activity observed for the volatile compounds from P. regnellii leaves.

Chemical composition of volatiles emitted by Ziziphus jujuba during different growth stages

The volatiles emitted in vivo by different organs (leaf, bud flower, flower, green and red fruits) of Ziziphus jujuba were analysed using HS-SPME-GC/MS. A total of 144 compounds were identified corresponding to 94.6–99.4% of the whole aroma profile of jujube samples. The main constituents detected were (E, E)-α-farnesene, (E)-β-ocimene, perillene, γ-terpinene, cis-sabinene-hydrate, trans-sabinene-hydrate and 4-terpineol. The SPME analyses of the collected samples showed different patterns of emission and can contribute to understand their ecological interactions and fruit production management.

ESSENTIAL OIL AND CHEMICAL CONESTITUENTS OF FENNEL PLANTS AS AFFECTED BY COMPOST/NPK AND BIOFERTILIZATION TREATMENTS

A field experiment was conducted during the two successive seasons of 2012/2013 and 2013/2014 to explore the effect of compost/NPK and biofertilization treatments on essential oil, photosynthetic pigments and herb NPK content of fennel plants. Obtained results revealed that the best three essential oil characteristics (essential oil %, essential oil yield per plant and per feddan), photosynthetic pigments (chlorophylls a, b and carotenoids) and herb content of N, P and K values were obtained due to the use of the full dose of mineral NPK, ¼ compost + ¾ NPK dose or ½ compost + ½ NPK dose with no significant differences being detected between such three fertilization treatments. Concerning biofertilization treatments, all of the prementioned essential oil determinations, photosynthetic pigments and herb NPK content traits were considerably augmented due to the dual treatment (Minia Azotein + phosphorein) followed by Minia Azotein, while phosphorein gave the least values. In regard to the interaction gave between the, two involved factors, the highest volatile oil determinations and chemical compositions values were given by fertilizing fennel plants with the full dose of mineral NPK, 25% compost + 75% NPK or 50% compost + 50% NPK in combination with dual biofertilizer treatments (Minia Azotein + phosphorein). It is recommended, to supply fennel plants with 50% compost + 50% NPK in combination with the dual biofertilization treatment (Minia Azotein + phosphorein), from the environmental and economical point of view, in order to maximize the fruit essential oil productivity.

The origin of the Zhubu mafic-ultramafic intrusion of the Emeishan large igneous province, SW China: Insights from volatile compositions and C-Hf-Sr-Nd isotopes

The Zhubu mafic-ultramafic intrusion of the Permian Emeishan large igneous province (LIP), SW China hosts a magmatic Ni, Cu and platinum-group element (PGE) deposit. It consists of a layered sequence with sub-horizontal modal layering wrapped by a sub-vertical marginal zone. Our new zircon U-Pb isotopic dating gives a mean age of 263.2±5.6Ma for the layered sequence. The volatiles extracted from the mineral separates of the Zhubu intrusion are composed of predominant H2O (11,769.84mm3·STP/g, STP-standard temperature and pressure) and minor H2 and CO2. The layered sequence has lower H2O but higher H2, CO2, H2S and SO2 contents than the marginal zone. The CO2 and CH4 extracted at 400–900°C and 900–1200°C have light δ13CCO2 varying from −17.45‰ to −7.10‰ and δ13CCH4 varying from −41.35‰ to −22.88‰. The pyroxene separates have significantly lower (87Sr/86Sr)i values (0.705882 to 0.708912) and slightly higher εNd (t=263Ma) values (−2.8 to 0.7) than the whole rocks. The εHf (t=263Ma) values of zircon crystals vary from −3.05 to +1.90. The chemical compositions of volatiles from the Zhubu intrusion indicate a slightly reduced condition and a H2O-rich parental magma. The C-Hf-Sr-Nd isotopes for the Zhubu intrusion are consistent with ~15wt% assimilation of the upper crust by a mantle-derived magma. The carbon isotopes indicate that a thermogenic component from sedimentary organic materials was present in the contaminated magma. A weak positive correlation between volatile and PGE contents, together with the C-Hf-Sr-Nd isotopes, indicates that sulfide saturation in the Zhubu magma was triggered by crustal contamination including the addition of volatiles.

Antioxidant activity, color chromaticity coordinates, and chemical characterization of monofloral honeys from Morocco

ABSTRACTThe bioprospecting of several monofloral Moroccan honeys was carried out. The antiradical activity expressed as mmol Trolox equivalents/kg of honey and evaluated by 2,2-diphenyl-1-picrylhydrazyl assay, ranged from 0.15 for euphorb honey to 1.08 for citrus honey. The antioxidant activity expressed as mmol Fe2+/kg and evaluated by ferric ion reducing antioxidant power assay, ranged from 0.96 for euphorb honey to 4.74 for orange honey. The total phenol content was evaluated by colorimetric assay, while the color attributes were evaluated as transmittance data. Significant Pearson correlation factors were found between total polyphenol amount and antioxidant activity and between color attributes and antioxidant activity. Furthermore the chemical composition of volatile organic compounds was determined. The volatile organic compounds chemical composition of the studied honeys was mainly represented by terpene and benzene derivatives, Maillard reaction products, isoprenoids, and hydrocarbons. The volatiles fingerprint, as well as a targeted high-performance liquid chromatography analysis of the polar components, was used to tentatively confirm the declared botanical origin of the samples studied.

Analysis of the Volatile Constituents of Alpinia pinnanensis

The chemical compositions of volatiles from Alpinia pinnanensis T. L. Wu & Senjen (Zingiberaceae) are being studied. The essential oils that were obtained by hydrodistillation were analyzed by GC (FID) and GC-MS. The components were identified by MS libraries and their LRIs. The essential oils content varied between 0.11% and 0.41% (v/w), calculated on a dry weight basis. Monoterpenes (21.0 - 60.7%) and sesquiterpenes (16.3 - 74.4%) are the main oil fractions. The leaf of A. pinnanensis afforded oil whose major compounds were 1,8-cineole (20.5%), 4-phenyl-2-butanol (19.5%) and α-phellandrene (10.8%) while the stem bark comprised mainly of 1,8-cineole (10.0%), β-elemene (8.7%), α-gurjunene (7.6%), β-pinene (7.3%) and (E,E)-farnesol (7.2%). On the other hand, (E,E)-farnesol (8.4%), α-gurjunene (6.2%), camphene (5.6%) and fenchyl acetate (5.4%) were the most abundant constituent of the root bark oil. However, α-cadinol (18.1%) and β-caryophyllene (11.4%), along with (E, E)-farnesol (6.3%) and β-pinene (6.1%) were the main constituents of the fruit oil. A comparative analysis of the compositional patterns of essential oils of A. pinnanensis with other Alpinia species grown in Vietnam revealed a marked variation in their chemical constituents.

Chemical composition of volatiles from the syconia of Ficus microcarpa and host recognition behavior of pollinating fig wasps

Chemical composition of volatiles from the syconia of Ficus microcarpa and host recognition behavior of pollinating fig wasps

Volatile compounds analysis and antioxidant, antimicrobial and cytotoxic activities of Mindium laevigatum.

Objective(s):Mindium laevigatum is an endemic plant of Iran and Turkey and is widely used as blood purifier, antiasthma and antidyspnea in traditional medicine. Chemical composition of volatile materials of the plant and its antioxidant, antimicrobial and cytotoxic activities were reported in this study.Materials and Methods:Simultaneous distillation-extraction (SDE) and GC-Mass-FID analysis were used for the plant volatile materials chemical composition identification and quantification. Several antioxidant tests including DPPH radical scavenging, hydrogen peroxide scavenging, reducing power determination, β-carotene-linoleic acid and total phenolic content tests were used for antioxidant activity evaluation. Antimicrobial and anticancer activities were also estimated using microbial strains, cancer cell lines and brine shrimp larva.Result:s: GC-Mass-FID analysis of volatile samples showed a total of 74 compounds of which palmitic acid (7.4-33.7%), linoleic acid (6.6-18.6%), heneicosane (1.3-9.6%) and myristic acid (1.4-6.0%) were detected as main volatile components. Moderate to good results were recorded for the plant in β-carotene-linoleic acid test. Total phenolic content of the extracts as gallic acid equivalents were estimated in the range of 15.7 to 79.6 μg/mg. Some microbial strains showed moderate sensitivities to plant extracts. Brine shrimp lethality test and cytotoxic cancer cell line assays showed mild cytotoxic activities for the plant.Conclusion:Moderate to good antioxidant activities in β-carotene-linoleic acid test and presence of considerable amounts of unsaturated hydrocarbons may explain the plant traditional use in asthma and dyspnea. These findings also candidate it as a good choice for investigating its possible modern medical applications.

Chemical compositions and volatile compounds of Tricholoma matsutake from different geographical areas at different stages of maturity.

Tricholoma matsutake is a commercially important edible fungus. Volatile compounds, chemical compositions, and nutritional values of fruiting bodies at different stages of maturity from different geographical areas were analyzed. The main volatile compounds in T. matsutake fruiting bodies were (E)-2-octenal, phenylacetaldehyde, 3-octanone, methyl cinnamate, benzaldehyde, and 1- octen-3-ol. Kinds and levels of volatile compounds from different geographical areas varied. As the fruiting bodies aged, levels of methyl cinnamate and 1-octen-3-ol gradually declined. Potassium was the most abundant element in T. matsutake fruiting bodies. Of 17 amino acids detected in fruiting bodies, glutamate was the most abundant. Volatile compounds, chemical compositions, and nutritional values of T. matsutake varied with age and geographical origin and can serve as chemical indicators for classication of T. matsutake from different geographical areas and at different stages of maturity.

Intraspecific Variation of the Volatile Chemical Composition of Myracrodruon urundeuva Fr. Allem. (“Aroeira-do-Sertão”): Characterization of Six Chemotypes

Myracrodruon urundeuva Fr. Allem. (Anacardiaceae) is the scientific designation of aroeira-do-sertao, a tree well dispersed through the Caatinga, the characteristic northeastern Brazil flora. Its trunk bark decoction is used to treat cutaneous affections, urinary and respiratory diseases and as a postpartum aseptic bath. This work reports the analyses of the essential oils from leaves of 62 specimens of aroeira-do-sertao. Analyses by 1H nuclear magnetic resonance (NMR) and gas chromatography coupled to mass spectrometry (GC-MS) of all oil samples permitted the characterization of all major components and, in consequence, the characterization of six different chemotypes of M. urundeuva, represented by the chemomarkers: myrcene, α-pinene, limonene, Δ3-carene, (Z) and (E)-β-ocimene.

HPLC Determination of the Alkamide Affinin in Fresh and Dry Roots of Heliopsis longipes (Asteraceae) and HS-SPME-GC-MS-TOF Analysis of Volatile Components

Heliopsis longipes (Asteraceae) is a plant whose roots are commonly used in Mexican cuisine as a substitute for hot pepper. This plant is also used in traditional medicine for its therapeutical properties. Previous reports detected the presence of affinin—an alkamide with analgesic properties—in extracts of H. longipes. Here, we describe the development of a high-performance liquid chromatography-UV detector method for the determination of the alkamide affinin (1) as the major component in fresh and dry roots of H. longipes. Compound 1 was quantitatively determined employing a Kromasil 100 C18 3 μm particle size column, using the isocratic mobile phase acetonitrile-water (55 + 45). The flow rate was 0.8 mL/min and the UV detection was at 213 nm. The limits of detection and quantitation were 0.0009 and 7.6 μg/mL, respectively. Compound 1 showed good linearity in the 75 to 150 μg/mL range; recovery was within 99.3 and 101.9 %. Quantities of affinin measured by this method ranged between 6.9 and 8.5 mg per gram of the dry and fresh roots; thus 1 could be used as marker for H. longipes. The LC method described here proved to be reliable, reproducible, accurate, and could be used for quality control of H. longipes medicinal materials. In addition, its volatile chemical composition is described and was assessed via GC-MS using headspace solid-phase microextraction; compounds were identified by matching against the standard mass spectral database of the National Institute of Standards and Technology (NIST). Twenty-eight recognized compounds represent 99.9 % of the total relative content of constituents from H. longipes roots.

Anti-Oxidant, Anti-Aging, and Anti-Melanogenic Properties of the Essential Oils from Two Varieties of Alpinia zerumbet.

Here, we investigated the anti-oxidant and anti-aging effects of essential oils (EOs) from the leaves of Alpinia zerumbet (tairin and shima) in vitro and anti-melanogenic effects in B16F10 melanoma cells. The anti-oxidant activities were performed with 2,2-diphenyl-1-picrylhydrazyl (DPPH); 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS); nitric oxide; singlet oxygen; hydroxyl radical scavenging; and xanthine oxidase. The inhibitory activities against collagenase, elastase, hyaluronidase, and tyrosinase were employed for anti-aging. The anti-melanogenic was assessed in B16F10 melanoma cells by melanin synthesis and intracellular tyrosinase inhibitory activity. The volatile chemical composition of the essential oil was analyzed with gas chromatography-mass spectrometry (GC/MS). The EO was a complex mixture mainly consisting of monoterpenes and sesquiterpenes. The results revealed that tairin and shima EOs showed strong anti-oxidant activities against DPPH and nitric oxide, hydroxyl radical scavenging activity, and xanthine oxidase inhibition. Compared to shima EO; tairin EO exhibited strong anti-aging activity by inhibiting collagenase, tyrosinase, hyaluronidase, and elastase (IC50 = 11 ± 0.1; 25 ± 1.2; 83 ± 1.6; and 213 ± 2 μg/mL, respectively). Both EOs inhibited intracellular tyrosinase activity; thus, reducing melanin synthesis. These results suggest that tairin EO has better anti-oxidant/anti-aging activity than shima EO, but both are equally anti-melanogenic.

A Survey of Chemical Compositions and Biological Activities of Yemeni Aromatic Medicinal Plants.

Yemen is a small country located in the southwestern part of the Arabian Peninsula. Yemen’s coastal lowlands, eastern plateau, and deserts give it a diverse topography, which along with climatic factors make it opulent in flora. Despite the introduction of Western medicinal system during the middle of the twentieth century, herbal medicine still plays an important role in Yemen. In this review, we present a survey of several aromatic plants used in traditional medicine in Yemen, their traditional uses, their volatile chemical compositions, and their biological activities.