The principal component analysis of antioxidant activities of Songgak, a traditional herbal drink in West Nusa Tenggara, Indonesia

Abstract

Songgak is a traditional herbal tea of the Sasak Tribe in Lombok Island, Indonesia, formulated to strengthen people's stamina. Songgak is composed of seven kinds of roasted spices: Piper nigrum L., Coriandrum sativum L., Piper retrofractum Vahl, Myristica fragrans Houtt, Syzygium aromaticum, Elaeocarpus grandiflorus, and Helicteres isora. This study aimed to assess the benefits of Songgak and its constituent spices by evaluating their antioxidant activities, total phenolic content (TPC) and flavonoid content (TPC). Antioxidant activity tests were performed on the water extract of Songgak, ethanolic extract of Songgak, and ethanolic extract of seven spices of Songgak including 2,2′- diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP) assay. The antioxidant activity using DPPH method showed that the water extract of Songgak has a strong categorisation of antioxidant activity with DPPH IC50 value of 63.78±4.29 µg/mL. The constituent species of Songgak with the strongest antioxidant activity was S. aromaticum. Total phenolic content (TPC) and total flavonoid content (TFC) of Songgak tea were 26.85±4.29 mg GAE/g and 6.99±0.29 mg RE/gram, respectively. The correlation between TPC, TFC, and antioxidant activities was determined using principal component analysis (PCA). The loading plot showed that TPC and TFC were strongly correlated with the antioxidant activity (FRAP method) of Songgak tea and its constituent spices. These results revealed that the presence of flavonoid and phenolic compounds in the seven herbal medicinal plants were responsible for the antioxidant properties of Songgak as a healthy herbal drink. Therefore, consuming Songgak every day can be beneficial for preventing various diseases involving free radicals.