Integrating In Vitro Culture, Phytochemical Analysis, and DNA Markers for Comprehensive Characterization of Ocimum...

The recognized medicinal potential of Ocimum sanctum (holy basil) and Ocimum basilicum (sweet basil) is largely underpinned by the structural diversity and abundance of their phytochemical constituents. The two species are well documented with regard to their medicinal effects, but there is a lack of comparative investigations linking in vitro biosynthetic potential with genetic diversity. Callus cultures allow for a sustainable alternative that can produce bioactive compounds similar to intact plants without the pressure exerted on natural populations. The present study compared the callus induction response, phytochemical profiles, and RAPD-based molecular diversity of O. sanctum and O. basilicum. Maximum callus proliferation was observed in O. sanctum on MS supplemented with 1.0 mg L^-1 2,4-D + 0.2 mg L^-1 BAP, while 0.2 mg L^-1 NAA + 0.2 mg L^-1 BAP was optimal for O. basilicum. Furthermore, in terms of analysis of the total yield, higher total phenolic and flavonoid contents have been detected in callus extracts and leaves of O. sanctum than in O. basilicum. HPLC analysis confirmed caffeic acid, which is the main compound in both species, rosmarinic acid, and kaempferol, the latter being exclusively found in O. sanctum. RAPD showed various polymorphic banding patterns indicative of polymorphism between the two species. The work correlated the in vitro phytochemical biosynthesis with the molecular level variations in genetics, which can be beneficially grasped for future metabolic exploitation, cultivar selection, and conservation strategies.