Pharmacognostic Specifications and RP-HPLC Analysis of Manilkara hexandra Stembark

Background: Manilkara hexandra (Roxb.) Dubard (Sapotaceae) is valued in traditional system of medicine as febrifuge, astringent, tonic, antiperiodic, antidysentric etc. Objectives: The current study aimed for establishing quality control parameters accompanied by development of validated Reversed-Phase Liquid Chromatographic (RP-HPLC) method of four bioactive flavonoids (quercetin, luteolin, kaempferol and apigenin) in stembark. Materials and Methods: The stembark was evaluated for complete pharmacognostical parameters such as macroscopy, microscopy, ash value and extractive values. Chromatographic separation was performed on a C₁₈ column with a mobile phase consisting of 0.5% orthophosphoric acid and 100% methanol (40:60 %v/v), at a flow rate of 1.0 mL/min. The analysis was performed using a UV detector at different wavelengths. The method was validated in terms of selectivity, linearity, accuracy, precision, robustness and recovery. Results: Transverse section of the stembark showed presence of rhytidoma, discontinuous rows of phloem fibres associated with idioblasts, ceretanchyma and few latex cells in phloem. In HPLC study, good linearity was observed over the investigated concentration range of 5-30 μg/mL for quercetin and luteolin; 2-64 μg/mL of kaempferol and 2-12 μg/mL of apigenin with correlation coefficient (r²) values greater than 0.998. The intra- and inter-day precision over the concentration range was <0.57% (relative standard deviation) and the accuracy were between 98.06 and 100.65%. The %RSD of recovery for all the analytes was 0.49-0.81%. Conclusion: The information derived on pharmacognostic parameters and validated HPLC method for estimation of four bioactives for M. hexandra, would aid as coherent measures for its quality assessment.