Antioxidant and cytotoxic activity of in Vitro raised dendrobium Amoenum wall. Ex lindl.

Abstract

Dendrobium amoenum Wall. ex Lindl., the most prominent epiphytic orchid, is recognized for its attractive blossoms and has been used in traditional medicine in various South Asian countries. D. amoenum yielded a variety of compounds, including amoenylin, iso-amoenylin, moscatilin, bibenzyl derivatives, phenols, phenanthrenes, and sesquiterpenoids. The study’s objectives were to assess the phenol, flavonoid, antioxidant, and cytotoxic activities of D. amoenum methanolic fractions grown in vitro. FMS medium enriched with 0.25 mg/l NAA and 10% CW produced the healthiest shoots (19.33±2.40) and shoot length (4.17±0.58cm). The highest root number (8.67±5.17) and root length (2.13±0.55cm), were found in IAA (0.25mg/l). The yellow fraction was found to have the highest phenolic (206.38 g GAE/mg extract) and flavonoid content (101.88 g QE/mg extract). The yellow, green, light green and dark green fractions of the methanolic extract inhibited DPPH free radicals (IC50 ) at values of 63.73±0.38 µg/ml, 179.76±1.47 µg/ml, 105.79±0.57 µg/ml, and 204.27±2.75 µg/ml respectively. At 200 µg/ml concentration, the green fraction inhibited the growth of HeLa (human cervical carcinoma) cells by 82.36±5.79%, the dark green fraction inhibited the growth of U2OS (osteosarcoma) cells by 64.75±3.41%, and the light green fraction inhibited the growth of Normal cells by 13.51±4.43%. Except for Normal cells, which are non-toxic to humans, the fractions of methanolic extract suppress cell growth by 50% against HeLa and U2OS cells. The antioxidant potential of the methanolic fraction of D. amoenum extracts is related to the presence of antioxidant-rich chemicals such as polyphenol derivatives, which have a high potential to inhibit the proliferation of cancer cells, elucidating the orchid's potential in alternative medicine toward medication development.