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The present study reports the isolation of two eudesmanolide type sesquiterpenoid lactones, viz. alantolactone and isoalantolactone, from the roots of Inula racemosa Hook L. and their chemical transformations using various reagents. All the compounds isolated and synthesized were assessed for their in vitro antifungal potential against Dreschlera oryzae, Fusarium moniliforme, and Alternaria triticina using spore germination inhibition method. To understand how the structure of sesquiterpene lactones relates to their antifungal function, structure activity relationships were studied. Isoalantolactone and its derivatives were found to be more toxic as compared to alantolactone and its derivatives. Among the different synthesized compounds, the bromoform derivatives were the most, while the methoxy derivatives were the least effective. All the compounds showed promising results against three test fungi with ED50 values less than 400 ppm.

Khusinol isolated from vetiver oil was subjected to various chemical modifications. Ester derivatives of khusinol were prepared with acetic anhydride and benzoyl chloride. Epoxides of khusinol were synthesized using perbenzoic acid, vanadium oxyacetylacetonate–t-butyl hydroperoxide, and N-bromosuccinimide– sodium hydroxide. All the compounds showed promising in vitro antifungal potential against Alternaria triticina, Drechslera oryzae, and Fusarium moniliforme with ED50 values in the range of 200–250 μg/mL.

Nematicidal potential of chloroform root extract of Inula racemosa and its fractions was investigated on egg hatching and mortality of root knot nematode Meloidogyne incognita. Egg masses and second stage juveniles (J2) of M. incognita were exposed to different concentrations (0.1-8.0 mg ml-1) of I. racemosa root extract and its fractions. Observations on egg hatch were recorded on 1st, 3rd, 5th, 7th and 9th day and those of mortality studies were recorded on 2nd, 4th, 6th, 8th and 10th day, respectively. Significant mortality as well as egg hatch inhibition was observed for all the tested components at 5 %. The root extract was found to be most effective in controlling egg hatching as complete inhibition was observed at 8.0 mg ml-1 concentration on 1stday of treatment and nonpolar fraction was most effective in causing mortality of J2 of M. incognita as 100 % inhibition was observed at 6.0 and 8.0 mg ml-1 concentration on 2nd day of treatment. Maximum inhibition of egg hatching was observed for root extract at 8.0 mg ml-1 concentration and 100 % mortality was observed for root extract as well as nonpolar fraction at the same concentration. The nonpolar fraction was most effective in causing mortality as maximum mortality was observed at 6.0 and 8.0 mg ml-1 concentration throughout the exposure time. Polar fraction was least effective among all the components both in egg hatch inhibition and J2 mortality of M. incognita. Both the activities showed concentrations as well as time dependence. Results show different role of tested components on egg hatching and mortality of root knot nematode. The root extract of I. racemosa and its fractions showed a potential to develop new nematicide.

A laboratory experiment was conducted to study chemistry and insecticidal activity of bay leaf oil, its fractions and isolated compounds against stored grain pest of wheat i.e.Tribolium castaneum Herbst. Bay leaf essential oil extracted from dried and powdered bay leaves was subjected to column chromatography to have its fractions. Extensive column chromatography of polar fraction yielded Eugenol and 7, 7 Dimethyl-3-methylene bicyclo [2.2.1] heptan-4-ol which were identified by spectroscopic techniques. Bay leaf oil was tested for its insecticidal activity at five different concentrations in the range 4-12 mg g-1respectively against F1 generation of red rust flour beetle adults. Maximum inhibition was observed at 12 mg g-1concentration. The activity was both time and concentration dependent. The fractions of bay leaf essential oil and the compounds isolated were tested at 4mg g-1 concentration. Polar fraction was found to be more active as compared to nonpolar fraction as 100 and 53.1% mortality was obtained on 30th day for polar and nonpolar fractions, respectively. Comparison of eugenol and 7, 7 Dimethyl-3-methylene bicyclo [2.2.1] heptan-4-ol showed complete mortality on 33rd and 35thday respectively , which revealed that adults of T. castaneum were more susceptible to eugenol.The results indicated that bay leaf essential oil may have potential to control stored grain pest, T. castaneum.

The aim of this study was to evaluate in vitro antifungal potential of carrot seed extracts, its essential oil, different fractions, isolated compounds, and their derivatives against three phytopathogenic rice fungi (Fusarium moniliforme, Bipolaris oryzae, and Rhizoctonia solani) using poisoned food technique. Carrot seed essential oil was extracted using hydrodistillation method and extracts were prepared using different solvents viz. dichloromethane, hexane, and methanol. The pure compounds daucene, carotol, and daucol were isolated using column chromatography and derivatized using different reagents. The study demonstrated that antifungal potential of all tested compounds varied in a dose dependent manner. Structure activity relationship of isolated and derivatized compounds showed that polar moieties possessed more antifungal potential as compared to non-polar moieties. The results suggested that carrot seed methanol extract and carotol possessed strong antifungal potential as compared to other components tested. PRACTICAL APPLICATIONS: Phytopathogenic fungi are the major problems causing harmful damage to the rice crop. Only available control of these diseases is synthetic fungicides but their repeated use led to serious environmental issues, residual toxicity, and development of resistance. Therefore, it's better to find some natural alternatives. The current study was conducted to evaluate in vitro antifungal potential of carrot seed essential oil, its constituents and extracts against phytopathogenic fungi of rice. The methanol extract and carotol possessed highest antifungal potential which might be due to their polar nature. This information may add a new dimensions to biological activity of these natural molecules mainly in the field of agriculture as fungal diseases are found to be associated with major losses in agriculture. Hence these compounds can act as natural antifungal agents against rice fungi.

Essential oil of carrot is produced and accumulated in the secretary ducts known as vittae. Phytochemical studies have shown that the major chemical components of carrot plant are polyphenols, flavonols, glycosides, alkaloids, saponins, sesquiterpenoids and essential oil. Chemical constituents of carrot seed essential oil obtainedby hydrodistillation have been the subject of frequent researches. The composition of essential oil varies with plant parts. The carrot essential oil possesses biological activities like antimicrobial, antibacterial, antifungal, herbicidal, antioxidant, anticancer etc. The health benefits of carrot essential oil can be attributed to its antiseptic, disinfectant, detoxifying, antioxidant, anticarcinogenic, tonic, carminative, depurative, diuretic and stomachic properties.Major components present in different parts of carrot plant are listed along with their chemical composition. The morphological details of plant, its essential oil, chemicalconstituents and biological activities have been discussed in this review.

In the present study, Dill (Anethum graveolens) seed essential oil, its nonpolar and polar fractions, compounds isolated and derivatized were evaluated for their antioxidant potential using different in vitro assays. The major compounds carvone, limonene, and camphor were isolated from dill seed essential oil using column chromatography and characterized using spectroscopic techniques. Among all the tested components for antioxidant activity, carveol and perillyl alcohol were most effective (IC50 values 10 mg/ml). All the tested compounds exhibited lower antioxidant potential than the standard. PRACTICAL APPLICATIONS: Oxidation of food products was delayed by compounds known as antioxidants. The use of synthetic antioxidant is restricted because of carcinogenicity in human servings and plant-based natural antioxidant are preferred due to safety and less toxicity. The aim of this in vitro study was to assess the antioxidant activity of the different constituents of dill seed essential oil. The present study revealed that carvone and its derivatives are potent scavengers of free radicals which might be due to the presence of unsaturated hydroxyl group. Thus, natural antioxidants are the important source of alternative medicines and natural therapy in the pharmaceutical industry.

Mentha leaf essential oil extracted from dried and powdered menthe leaves was subjected to column chromatography to obtain its fractions. Three compounds namely pulegone, menthol, p-cymene were isolated from polar fraction. Menthol was chemically transformed to menthone using pyridinium chlorochromate. All the compounds were identified by spectroscopic techniques. Mentha leaf essential oil (pure) was tested for its insecticidal activity at five different concentrations in the range 50–500 μg g−1 respectively against F1 generation of red rust flour beetle (Tribolium castaneum Herbst.) adults. Maximum inhibition was observed at 500 μg g−1. The activity was both time and concentration dependent. The fractions of mentha leaf essential oil and the compounds isolated were tested at 250 μg g−1 concentration. Polar fraction was more active as compared to the non-polar fraction. Adults of the beetle were more susceptible to menthone as complete corrected per cent mortality was observed on 22nd d in menthone as compared to 25 d for menthol. The results indicated that mentha leaf essential oil may have potential to control infestation of wheat by T. castaneum.

Alantolactone and isoalantolactone were isolated from powdered roots of Inula racemosa H. using Soxhlet extraction followed by the column chromatography. Pyrazolines of alantolactone and isoalantolactone were synthesized using diazomethane, diazoethane and diazopropane. The structure elucidation of the compounds were carried out using IR and 1H NMR spectroscopic techniques. All the compounds were screened in vitro for their antifungal potential at various concentrations against Alternaria brassicae and Penicillium italicum using spore germination inhibition technique and against Rhizoctonia solani by poisoned food technique. All the compounds exhibited fairly good fungitoxicity against the test fungi with ED50 values of less than 500 μg mL − 1.

Extraction of ajwain seed (Trachyspermum ammi (L.) essential oil, isolation and derivatization of compounds and testing of insecticidal activity against rice weevil are reported. GC-MS analysis of the essential oil showed the presence of mainly monoterpene hydrocarbons (35.91%) and oxygenated monoterpenes (60.57%). Thymol (31.4%) was the major constituent whereas α-pinene (4.44%) and silphine (3.53%) were the minor compounds. The essential oil, its fractions and thymol along with its derivatives (thymyl phenyl ether, thymyl acetate, o-nitro thymol and azo-derivatives) were evaluated against Sitophilus oryzae at four concentrations (1.0–4.0 mg g−1) for their effect on insect mortality and repellency. Thymol was more effective as compared to essential oil or its fractions. Among the thymol derivatives, thymyl phenyl ether was the most effective and showed complete mortality on the 5th d of exposure. The other derivatives did not show complete mortality even after 7 d of exposure. Based on the results, thymol could be used as a stored grain protectant against S. oryzae.

The aim was to study the composition of ajwain seed oil by gas chromatography-mass spectrometry (GC-MS) and to evaluate antioxidant activity of ajwain seed oil, its fractions, extracts, thymol, and its derivatives. GC-MS analysis of ajwain seed essential oil showed the presence of 47 compounds. Thymol (31.40%) was found to be the major component while γ-terpinene, isobornyl isobutyrate, and p-cymene were minor compounds. The antioxidant potential of selected components was evaluated using 2, 2-diphenyl-1-picrylhydrazyl, hydroxyl, nitric oxide radical scavenging and ferric reducing antioxidant power assays. Results demonstrated that methanol extract exhibited higher antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl (IC50 value 130 µg/mL), Hydroxyl radical (IC50 value 120 µg/mL), nitric oxide (IC50 value 90 µg/mL) scavenging assays, and highest ferric reducing antioxidant power (FRAP) value (780 µg Fe (II)/g dry weight) as compared to hexane and dichloromethane extracts. Total phenolic (16.52 mg gallic acid equivalents/g) and flavonoid contents (3.89 mg quercetin equivalent/g) were also found to be higher in methanol extract compared to other extracts and ajwain oil. Practical applications Degradation of food materials by oxidation and its prevention during production, storage, and distribution is an important issue in the food industry. Due to the potential carcinogenic effect of some synthetic antioxidants, much attention has been paid to naturally-derived compounds having potential to act as antioxidants. The present study revealed that the methanol extract of ajwain seeds which contained terpenoids, phenols, and flavonoids as essential phytochemicals have high antioxidant properties, which can provide opportunities for use in pharmaceutical, nutraceutical, and food industries.

Modern agriculture practices have been great promise for economic development of nation. Farm productivity isdirectly proportional to use of agrochemicals as observed from the first green revolution. In recent years, chemical pesticides have become the most important consciously-applied form of pest management. A pesticide is any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any pest. The main use of pesticides in India is in agriculture and public health sector to combat the various pests and diseases that affect man. The amount of pesticides used in India is very low (only 0.5 kg/ha) as compared to other developed countries even then we have much higher pesticide residues in food of our country. The overall demand of pesticides in country has increased during the last decade. The highest rate of increase in pesticide demand was observed in Andhra Pradesh followed by Maharashtra, whereas, Karnataka shows the significant decrease in pesticide demanded during the 2005–06 to 2012–13.

The synthesis of several epoxides ranging from monoterpenes to sesquiterpene lactones using urea hydrogen peroxide as oxidant and tungstophosphoric acid as catalyst is reported.