Qualitative phytochemical analysis, enzymatic and non-enzymatic antioxidant activities in stems and leaves of Vanilla planifolia (Orchidaceae)

Abstract

Vanilla planifolia, commonly known as vanilla orchid, is an epiphytic plant native to Mexico. This plant is used in the food and pharmaceutical industries due to its flavour and antioxidant properties. Vanilla bean is becoming more expensive due to current market demand. Consequently, less than 1% of the vanillin used in the market is derived naturally from vanilla plants. The present study was conducted to identify the phytoconstituents and the antioxidative activities (enzymatic and non-enzymatic) in the stems and leaves of V. planifolia collected from Temerloh, Pahang. Phytochemical screening revealed the presence of alkaloids, saponins, flavonoids, tannins, terpenoids, cardiac glycoside, carbohydrate and reducing sugar in both V. planifolia stems and leaves. Vanilla stem contains more ascorbic acid (94.49±2.92 µg/mL) and carotenoids (2.61±0.08 µg/mL) as compared to that of leaves (71.79±2.05 µg/mL and 0.82±0.07 µg/mL, respectively). However, there was no significant difference (P>0.05) in α-tocopherol concentration. Enzymatic activities showed that ascorbate peroxidase (APX) and catalase (CAT) were more distinct in leaves while more peroxidase (POD) activities were observed in the stems. High concentrations of phytochemical elements with high antioxidant activities in stems and leaves showed that V. planifolia is a promising source of antioxidants.