PHYSICOCHEMICAL AND HR-LCMS ANALYSIS OF SECONDARY METABOLITES PRESENT IN HONEY COLLECTED FROM DIFFERENT

Abstract

This study examined the quality and composition of Nepalese honeys by analyzing their physicochemical properties, antioxidant potential, and secondary metabolite profiles. Thirteen honey samples were collected from various farms across Nepal during November and December 2023, representing diverse floral sources such as Rudilo (Pogostemon benghalensis), Chiuri (Diploknema butyracea), Mustard (Brassica napus), Rhododendron (Rhododendron arboreum), Litchi (Litchi chinensis), and Fapar (Fagopyrum esculentum). The analysis focused on key physicochemical parameters, including moisture content and electrical conductivity. Antioxidant capacity was evaluated using DPPH, while secondary metabolites were profiled using High-Resolution Liquid Chromatography-Mass Spectrometry (HR-LCMS). Among the key constituents identified were naringenin-7-O-glucuronide, chlorogenic acid, 6- demethoxycapillarisin, and ophthalmic acid. The moisture content of the honey samples ranged from 13.86±0.02% to 19.89±0.03%, with the highest value observed in sample H2 (19.89±0.03%). Electrical conductivity ranged from 0.20±0.02 to 1.72±0.02 mS/cm, with sample H12 exhibiting the highest value (1.72±0.02 mS/cm). All honey samples exhibited acidity, with pH values ranging from 3.86 to 4.95, aligning with the typical pH range found in honey. Sample H6 displayed a notably higher pH (4.95±0.02) compared to the other samples. Citric acid content ranged from 14.04±0.02 to 68.64 ±0.03mg/100g, demonstrating an inverse correlation with pH, as evidenced by the higher citric acid level in sample H5 (68.64 ±0.02mg/100g) which corresponded to a pH of 3.86±0.02. Lactic acid content varied between 12.05±0.02and 19.04±0.02mg/100g across the different floral origins, with sample H5 exhibiting the highest concentration (19.04 mg/100g). The riboflavin content varied between 0.01 ± 0.001 mg/100g and 0.09 ± 0.004 mg/100g, with sample H7 (0.0187 mg/100g) representing a typical level for Apis cerana honey. Antioxidant activity, as measured by DPPH, ranged from 33.24% to 53.10%, with sample H5 displaying the highest activity (53.10%). The IC50 values ranged from 1158.08 μg/mL to 1662.63 μg/mL. Total phenolic content ranged from 21.71±3.42 to 72.02±2.103 mg GAE/100mg/ml, with H13 honey showing significantly higher levels compared to other samples. Similarly, total flavonoid content ranged from 9.82±0.96 to 38.025±1.350 mg GAE/100mg/ml, with H13 honey again exhibiting significantly higher levels. These findings emphasize the significant influence of mention parameter above on honey quality in Nepal, providing a scientific basis for applications such as targeted marketing, quality control, and exploration of potential health benefits. This research provides important insights into Nepalese honeys and their potential uses.