A COMPARATIVE STUDY OF THE PHYTOCHEMICALS, ANTIOXIDANT AND ANTIBACTERIAL POTENTIAL OF METHANOLIC EXTRACTS OF TRICHOSANTHES CUCUMERINA (L.) VAR. CUCUMERINA UNDER IN VITRO CULTURE AND NATURAL CONDITIONS

摘要

Objective: To compare the phytochemicals, antioxidative capacity and antibacterial profile of methanolic extracts of callus and naturally propagated plant species-Trichosanthes cucumerina (L.) var. cucumerina and to optimize an ideal protocol for in vitro callus and shoot induction. Methods: The sterilized seeds of Trichosanthes cucumerina (L.) var. cucumerina were inoculated in half Murashige and Skoog (MS) basal medium devoid of growth hormones to raise aseptic seedlings. Explants from aseptic seedlings used for callus induction in MS medium fortified with varying combinations of N 6 –Benzyl amino purine (BAP), 1-Naphthalene acetic acid (NAA) and 2,4–Dichlorophenoxy acetic acid (2,4-D). For in vitro soot induction, MS medium supplemented with different concentrations of 2,4-D, BAP and Kinetin-either alone or in combinations were employed. The callus harvested on 21 st and 45 th days were analyzed for a comparison of the influence of age of callus on the quantity of secondary metabolites. For a comparison with the naturally grown plant, all experiments were carried out with extracts from callus and wild plants. The antioxidant capacity of methanolic extracts was evaluated by 2,2-Diphenyl-1 Picryl Hydrazyl (DPPH) free radical scavenging assay and Ferric Reducing Antioxidant Power (FRAP) analysis. The antibacterial activity of were screened by the agar diffusion method using pathogenic bacteria such as Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus and documented through measurement of the diameter of growth inhibition zone (IZ). Results: The results on in vitro culture indicated that MS medium with BAP (0.5 mg/l) and 2,4-D (1 mg/l) was ideal for callus induction. For shoot induction, supplementation of MS medium with BAP-0.5 mg/l, 2,4,D-1.0 mg/l and Kinetin-0.5 mg/l was found to be most favourable. Direct root induction from the callus was found to occur in medium fortified with BAP-0.5 mg/l, 2,4, D-0.5 mg/l and NAA-1.0 mg/l. The phytoconstituents quantified were alkaloids, flavonoids, tannins, phenols and terpenoids and their levels were higher in wild plant in comparison to callus. Naturally grown plant possesses higher free radical scavenging ability and ferric reducing power than callus. Results of antibacterial activity indicated that the Gram-positive strain ( Staphylococcus aureus ) was more sensitive than the Gram-negative bacteria ( Escherichia coli and Pseudomonas aeruginosa ). The highest antibacterial activity recorded for naturally propagated plant extract against S. aureus (IZ = 13 mm) and was quite comparable with standard antibiotic cephatoxim (IZ = 20 mm) at 100mg concentration. Conclusion : Results concluded that this overexploited medicinal plant with lesser seed longevity could be successfully propagated by in vitro methods. The phytoconstituents with antioxidative and antibacterial potential were more abundant in naturally propagated plants than undifferentiated callus tissue. The extracts are potent antibacterial agents.