Evaluation of phytochemical profile and antioxidant activity of some medicinal plants seed extracts obtained by traditional and modern (green) extraction methods

The medicinal plants have been one of the major sources of medicines since the beginning of civilization. There is high demand for plant based medicines, nutraceuticals and cosmeceuticals all across the globe. Herbal medicines are becoming more and more popular in recent years with their over increasing acceptability in both developing and developed countries. All parts of the plant leaf, stem, bark, root, flowers, fruits, seeds, peels, are therapeutically useful. But flowers, seeds and peels are less utilized. Seeds are generally thrown into environment and these waste disposal has become a critical global problem. But they have a rich source of many valuable bioactive compounds especially phenols and flavonoids because of which they can be used therapeutically. In the present work, 6 plant seeds viz. Annona squamosa L., Carica papaya Linn. (Un-ripe), Carica papaya Linn. (Ripe), Ceiba pentandra L. Gaertn., Trachyspermum ammi L. and Trigonella foenum - graecum L. were screened for their phytochemical profile and antioxidant efficacy using different extraction techniques. The seeds were extracted by different extraction methods viz. Traditional methods - decoction, maceration and Modern methods - microwave assisted extraction and ultrasonic assisted extraction. The phytochemicals or bioactive components evaluated were total phenols, phenolic acids, flavonoids, flavonols and proanthocyanidin content. In vitro antioxidant activity in terms of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, Superoxide anion free radical (O2-) scavenging activity, 2, 2’-Azino-bis-(3-ethyl) benzothiazoline-6-sulfonic acid (ABTS) radical cation scavenging activity and Ferric reducing antioxidant power (FRAP) was evaluated. All the extracts showed varied levels of phytochemical and antioxidant activity. But the best activity was shown by modern methods especially UAE. Thus, seeds can be profitably, beneficially employed as a rich source of bioactive compounds which can be effectively utilized as a source of natural antioxidant and reduce environmental pollution.