Volatile composition and sensory properties of Indian herbal medicine-Pavonia odorata-used in Ayurveda.

The chemical composition of volatile oil obtained from aerial parts of Pavonia odorata were investigated using gas chromatography-mass spectrometry (GC-MS). Its aroma-active compounds were identified using gas chromatography-olfactometry (GC-O) and aroma extraction dilution analysis (AEDA). In order to determine the relative contribution of each compound to the aroma of P. odorata, relative flavour activity (RFA) was calculated. The hydrodistillation of P. odorata afforded yellowish oil and the yield was 0.009% (w/w) with a spicy, sweet, and green odour. Eighty-five compounds were identified in the oil by GC-MS; the major constituents of the volatile oil were ageratochromene (11.95%), palmitic acid (9.95%), hexahydrofarnesyl acetone (5.96%), β-eudesmol (4.53%) and β-caryophyllene oxide (3.08%). The most characteristic aroma compounds in the volatile oil were identified for β-caryophyllene oxide (FD-factor = 128, spicy), (E)-pinocarveol (FD-factor = 64, sweet), 3-butylpyridine (FD-factor = 64, spicy), and 2-nonanone (FD-factor = 32, green) by GC-MS, GC-O and AEDA. It seems that these compounds are responsible for the spicy, sweet and green odour of the aerial parts of P. odorata. The antioxidant activity of the volatile oil was also investigated by the oxygen radical absorbance capacity (ORAC) assay using fluorescein (FL) as the fluorescent probe. The ORAC value of the oil was 594.2 ± 25.9 μM TE/g. The results indicated that the volatile oil from the aerial parts of P. odorata could be considered as a natural antioxidant effect agent.