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 < 0.16 mg/ml), whereas camphor was least 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.

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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 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.

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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 1 H 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 ED 50 values of less than 500 μg mL −1 .

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