Meta-topolin induced in vitro regeneration in Crinum brachynema (Amaryllidaceae): a critically endangered and endemic medicinal plant of India

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English. Crinum brachynema (Amaryllidaceae) is an endemic and critically endangered bulbous medicinal plant of the Northern Western Ghats of India. This species contains an important and promising alkaloid called galanthamine (GAL), an antiAlzheimer drug. This investigation aimed to establish a reproducible protocol for in vitro regeneration of C. brachynema using twin scales as initial explants for the first time. Thus, cultures were established on Murashige and Skoog (MS) medium with cytokinins (6-benzyladenine (BA), and meta-Topolin (mT). The establishment and growth of shoots from the explants was achieved on MS medium supplemented with BA alone and in combination with 1-naphthaleneacetic acid (NAA). In vitro shoots were cultured on MS medium containing 0.5–10 µM of mT, of which 5.0 µM mT gave the highest shoot regeneration frequency (11.10). In general, mT proved superior as cultures produced a maximum number of regenerants compared to the control. Rooted plants with bulblets were successfully acclimatized in the greenhouse where they were phenotypically similar to the mother plants. Antioxidant activity was estimated using oxygen radical scavenging capacity (ORAC) model. Cultures on mT exhibited a significant increase in antioxidant capacity compared to the control. These findings highlight the beneficial effect and validate the rising importance of mT for in vitro regeneration studies. This study will serve as a potential protocol to conserve and restore the medicinally important C. brachynema, while the regenerated C. brachynema may be subsequently manipulated to further increase the accumulation of antioxidant potential.