Seasonal dynamics of phytometabolites content in Assam tea, Camellia sinensis var. assamica by LC-MS/MS: Implications for quality

Abstract

The study examines the seasonal variation in phytometabolite content in Camellia sinensis var. assamica, a prevalent tea variety in Northeast India. Focusing on both bud and dormant leaf (banjhi) samples harvested during the monsoon, autumn, and winter seasons, the research aims to assist cultivators in selecting optimal harvesting times for tea production. An LC-MS/MS method was developed and validated for phytometabolite quantification. Epigallocatechin gallate (EGCG) emerged as the most abundant catechin, with concentrations ranging from 78.01±13.31–125.21±5.65 µg/mg in buds during the monsoon and decreasing to 17.86±1.22–51.11±1.21 µg/mg in winter. Banjhi leaves exhibited even higher EGCG levels, from 203.86±21.06–312.58±28.23 µg/mg in the monsoon, dropping to 74.43±15.22–97.52±8.47 µg/mg in autumn. Similarly, epicatechin gallate concentrations in buds ranged from 17.04±2.57–24.78±1.15 µg/mg in the monsoon and decreased to 5.36±0.39–11.16±1.74 µg/mg in winter, while banjhi leaves showed a decline from 63.61±1.60–72.72±1.23 µg/mg in the monsoon, dropping to 12.73±2.07–15.35±1.33 µg/mg in autumn. The study also noted seasonal variations in catechin hydrate, caffeine, gallic acid, theanine, and theaflavin. These findings underscore the importance of harvest timing for maintaining tea quality and optimizing cultivation and processing practices for sustainability amid environmental changes.