Isolation, Characterization and Quantification of Isoflavone in Momordica dioica Roxb. Ex Wild (Cucurbitaceae) Fruits

Summary: Momordica dioica Roxb. Ex Wild (Cucurbitaceae) is known for anti-inflammatory, hepatoprotective, antimicrobial, antifungal and anti-diabetic activities. Some other species of genus Momordica along with this are also known for their anti-ovulatory, abortificient and anti-implantation activities which may be correlated to presence of isoflavone which acts like phytoestrogens in these plants. In this study, isoflavone daidzein was isolated from the fruits of M. dioica by soxhlet extraction followed by column chromatography. The isolated compound was identified by UV visible spectroscopy, IR spectroscopy, Mass spectrum, 1H-NMR and 13C-NMR, TLC and chemical test. Reverse phase high performance liquid chromatography (RP-HPLC) method has been developed for quantification of daidzein by using C-18 column (250 x 4.6, 5-μm) with an isocratic mobile phase, methanol and water containing 0.1% ortho-phosphoric acid (60:40 v/v) at a flow rate of 1.0 ml/min. The wavelength of maximum absorption (λmax) selected for quantification of daidzein was 255 nm. Calibration plot for daidzein was found to be linear with correlation coefficient (r2 = 0.9997) and regression equation (y = 60805x – 77107). The amount of daidzein present in M. dioica fruits was found to be 0.03% w/w. The developed method has been validated for accuracy, precision and specificity and successfully applied for quantification of isolated compound in M. dioica. Thus, daidzein could be used as phytochemical markers for the quality control of this plant as well as other species of genus Momordica. Industrial relevance: Daidzein is naturally occurring isoflavone found mainly in soybean and has been credited with performing several health promoting functions. Soybeans are rich source of isoflavone. Momordica dioica plant is found throughout the India. Fruits are used as vegetables. These fruits are cheap and easily available in India. Hence these fruits can be utilized as good source of daidzein for the herbal industries as well as human beings. This paper gives simple method for isolation of daidzein form these fruits. The RP-HPLC method developed can also be extrapolated for the standardization of herbal formulation containing daidzein. Keywords: Momordica dioica; HPLC; Daidzein; Isoflavone; Quantitative estimation.