Vitamin C Composition and Antioxidant Activity Assessment of Herbal Kombucha Tea from Bidara Leaves (Ziziphus mauritiana Lam) / Kandungan Vitamin C dan Uji Aktivitas Antioksidan Teh Herbal Kombucha Daun Bidara (Ziziphus mauritiana Lam)

Background: Bidara leaves (Ziziphus mauritiana Lam.) have long been used in traditional medicine due to their bioactive compounds, such as flavonoids, tannins, and vitamin C. Fermenting bidara leaves into kombucha has the potential to enhance antioxidant activity through bioconversion processes carried out by starter microbes (Acetobacter xylinum and Saccharomyces cerevisiae). However, scientific data regarding the vitamin C profile and antioxidant activity of bidara leaf kombucha remain limited. Objective: This study aims to analyze the vitamin C content and antioxidant activity of bidara leaf herbal kombucha, as well as to characterize the quality of the simplisia based on the Indonesian National Standard (SNI) 4324:2014. Methods: This descriptive study involved: (1) preparation of bidara leaf simplisia, (2) 12-day kombucha fermentation, (3) phytochemical screening, (4) determination of vitamin C content using UV-Vis spectrophotometry (λ = 266 nm), and (5) antioxidant activity assay using the DPPH method (λ = 517 nm). Results: The bidara leaf simplisia met the SNI quality standards, with a moisture content of 5.33% and a total ash content of 6.73%. Phytochemical screening identified the presence of flavonoids, saponins, tannins, glycosides, steroids/triterpenoids, and alkaloids. The vitamin C content of the kombucha was 0.009 mg/g, while the IC₅₀ value for antioxidant activity was 621.2158 µg/mL, which falls into the weak category. Conclusion: Bidara leaf kombucha contains bioactive compounds and vitamin C, with weak antioxidant activity. Fermentation increases antioxidant activity compared to non-fermented bidara tea infusion (IC₅₀ = 1129.0069 µg/mL), although it remains lower than that of pure vitamin C (IC₅₀ = 3.0710 µg/mL).

Latar Belakang: Daun bidara (Ziziphus mauritiana Lam.) telah lama dimanfaatkan dalam pengobatan tradisional karena kandungan senyawa bioaktif seperti flavonoid, tanin, dan vitamin C. Fermentasi daun bidara menjadi kombucha berpotensi meningkatkan aktivitas antioksidan melalui proses biokonversi oleh mikroba starter (Acetobacter xylinum dan Saccharomyces cerevisiae). Namun, data ilmiah mengenai profil vitamin C dan aktivitas antioksidan kombucha daun bidara masih terbatas. Tujuan: Penelitian ini bertujuan untuk menganalisis kadar vitamin C dan aktivitas antioksidan teh herbal kombucha daun bidara serta mengkarakterisasi mutu simplisia berdasarkan standar SNI 4324:2014. Metode: Penelitian deskriptif ini melibatkan: (1) preparasi simplisia daun bidara, (2) fermentasi kombucha selama 12 hari, (3) skrining fitokimia, (4) uji kadar vitamin C dengan spektrofotometri UV-Vis (λ=266 nm), dan (5) uji aktivitas antioksidan menggunakan metode DPPH (λ=517 nm). Hasil: Simplisia daun bidara memenuhi standar mutu SNI dengan kadar air 5,33% dan kadar abu total 6,73%. Skrining fitokimia mengidentifikasi senyawa flavonoid, saponin, tanin, glikosida, steroid/triterpenoid, dan alkaloid. Kadar vitamin C kombucha adalah 0,009 mg/g, sedangkan nilai IC50 aktivitas antioksidan sebesar 621,2158 µg/mL tergolong kategori lemah. Kesimpulan: Kombucha daun bidara mengandung senyawa bioaktif dan vitamin C dengan aktivitas antioksidan lemah. Fermentasi meningkatkan aktivitas antioksidan dibanding seduhan teh non-fermentasi (IC50 1129,0069 µg/mL), namun masih lebih rendah daripada vitamin C murni (IC50 3,0710 µg/mL).