Effect of Lupeol on Growth, Phytochemistry, and Antioxidant Potential of Brassica Nigra Shoot Tip Culture

Abstract

Brassica nigra, also known as Black Mustard, is an important medicinal plant with a wide range of pharmacological properties. Lupeol belongs to the triterpenoid family. It is a secondary metabolite that occurs naturally and is known to play an essential role in the complex systems of plant development and defense. Present study aims to investigate the effects of different concentrations of lupeol (1 µM, 5 µM, and 10 µM) on the growth characteristics, phytochemical content, as well as enzymatic and non-enzymatic antioxidant responses in Brassica nigra shoot tip culture. Among all tested samples optimal concentration for growth enhancement was observed at 10 µM lupeol. Both root and shoot length showed significant increases, with 109% and 77% increments. Fresh weight of roots increased up to 243% while dry weight enhanced up to 132% at 10 µM lupeol. Likewise, fresh weight (120%) and dry weight (103%) of shoots increased at 10 µM lupeol. Maximum total phenolic content was observed to increase at 10 µM lupeol in roots (87%) and shoots (98%). Similarly, flavonoid content showed 24% increase in roots and a 100% increase in shoots at 10 µM lupeol. Superoxide dismutase activity in roots and shoots of plants was found higher at 10 µM lupeol 160%, and 145%, respectively. Similarly, increase in the antioxidant enzyme (POD) activity by 246% in roots and 722% in shoots, respectively. DPPH assay revealed FRSA of 59% and 53% at 10 µM lupeol concentration of roots and shoots, respectively. Maximum ABTS scavenging activity of roots (47.8%) and shoots (47.3%) was observed at 10 µM lupeol. Significant Metal chelating activities of lupeol treated roots and shoots confirm their function as an efficient metal chelator agent at 10 µM lupeol by 52% and 49.4%, respectively. The total reducing potential of B. nigra roots (123%) and shoots (396%), total antioxidant potential of B. nigra roots (300%) and shoots (258%) were all gradually increased at 10 µM lupeol. This study shows the significance of lupeol as a promising elicitor and as a protective agent against oxidative damage in plants.