Development and validation of RP-HPLC method for vicenin-2, orientin, cynaroside, betulinic acid, genistein, and major eight bioactive constituents with LC-ESI-MS/MS profiling in Ocimum genus.

Background. Ocimum genus, known as Tulsi or Basil, is a prominent botanical class in Asian culture, especially in India. The leaves have immunomodulatory, antioxidant, stress-relieving, and adaptogenic roles in traditional and modern medicine, with prominent usage in herbal teas and nutraceuticals. Objective. An high-performance liquid chromatography-photodiode array (HPLC-PDA) method was developed and validated for quantification of vicenin-2, orientin, cynaroside, betulinic acid, genistein with syringic acid, rosmarinic acid, eugenol, carnosic acid, oleanolic acid, ursolic acid, luteolin, and apigenin and was confirmed using a novel electrospray ionisation-mass spectrometry (ESI-MS/MS) method in the Ocimum genus samples. Method. The methodology parameters were developed on an reverse phase (RP) C18 column with a gradient elution of 1 mL/min flow rate for 0.1% o-phosphoric acid and acetonitrile at 210 and 340 nm wavelengths. Results. The validation data for 13 bioactive compounds showed good linearity (r2 > 0.99) with sensitive LOD (0.034-0.684 µg/mL) and LOQ (0.100-2.068 µg/mL)...