Quantitative Analysis of the Flavonoid Mesquitol in the Medicinal Plant Prosopis juliflora with Seasonal Variations in Marigat, Baringo County-Kenya

Several studies indicate that mesquitol exhibits significant free-radical scavenging properties, antioxidant and α-glucosidase inhibitory properties. This makes it a useful resource with potential for exploitation in both agro-food and pharmaceutical industries. The heartwood of the plant P. juliflora is noted to contain very high levels of the flavan-3-ol compound mesquitol. Previous studies showed that in non-tropical countries like the United States of America where they experience four seasons in a year, mesquitol shows varying seasonal abundance with the least abundant season being the winter period. Meanwhile limited data exists on its abundance trends in tropical arid and semiarid regions that only experience the dry and wet seasons in a year. Plants samples of two distinct age groups were collected during the dry and wet seasons and extracted serially via a soxhlet apparatus after which column chromatography was used to assist in the process of mesquitol isolation. Thin layer chromatography assisted in pooling of fractions with similar Rf values. The Rf values were compared to available literature to ascertain fractions that contained mesquitol. A HPLC-UV method was developed and validated illustrating high accuracy and precision for the quantification of the mesquitol content in different P. juliflora samples. On evaluation, mesquitol was found to be more abundant during the wet seasons reaching 642.893 μg/ml as compared to 181.245 μg/ml for dry seasons. This abundance could be attributed to chemo-seasonal dynamics that have been witnessed to affect biosynthesis and deposition of phyto-compounds in plants. The developed and validated HPLC method, illustrated satisfactory quantification of mesquitol at 3-6% of the crude extract. This paper presents useful information on seasonal abundance dynamics of mesquitol in the tropics as a basis for the resource valorization.