As shown in Fig. 4, the cumulative contribution of the first and the second principal components attained 97.99%. PC1 was highly contributed by 6-gingerol (0.818), 8-gingerol (0.718), 10-gingerol (0.610), 6-shogaol (0.466), TPC (0.797), TFC (0.975), AEAC (0.712), FRAP (0.942) and ABTS (0.907)