Secondary Metabolites Accumulation in Turmeric Curcuma longa L.) Cultivated by Ethnic Communities in the Northern Mountain of Vietnam

Turmeric (Curcuma longa L.) is a culturally significant spice and medicinal crop grown by ethnic minority communities, including the Hmong, Dao, Thai, and Muong, in Vietnam's Northern Mountain region. It plays a vital role in traditional rituals, cuisine, and textiles. This study examined the accumulation of tannins, flavonoids, saponins, alkaloids, and curcuminoids in turmeric rhizomes cultivated in Lai Chau and Bac Kan provinces. The results showed that turmeric harvested at 9–10 months contained the highest levels of bioactive compounds, particularly curcuminoids. Ethnic-cultivated turmeric (ECT) from Lai Chau and Bac Kan had curcuminoid contents of 7.94% and 6.04% (fresh mass), surpassing the typical 3–5% in Vietnamese turmeric. While Lai Chau maintained stable curcuminoid levels, Bac Kan showed a slight decline after 11 months, likely due to environmental factors. ECT's rich phytochemicals offer potential for functional foods and biotherapeutics, supporting the cultural heritage and economic sustainability of ethnic communities in Vietnam's Northern Mountains.