3.3. Active principle contents
The active principle contents were determined in terms of the
total phenolic content. The TPC of the sticky rice husks (RD6)
extracted for 60 and 120 min were higher than Khao Dawk Mali
(KDML) 105 rice grown in northeastern Thailand, which had the
highest content of GAE (220 0.3 mg GAE/g extract) (Butsat and
Siriamornpun, 2010). In addition, the TFC was determined due to
the importance in cosmetics for wrinkle treatment (Churienthong
et al., 2010). The active principle contents were consistent with
antioxidant activity and extract yield. The longest time of extraction
resulted in the highest active principle content (Table 1). Furthermore,
refluxing for 120 min significantly extracted more active
contents than those of shorter times (p < 0.05).