Phytochemical properties of Medinilla speciosa leaf extract and its antibacterial activity against Burkholderia sp

Medinilla speciosa, also known as parijoto, is native to Indonesia, Malaysia, and the Philippines. It is a member of the Melastomataceae family. The plant is used as a traditional medicine by boiling or brewing. Pregnant women consume the fruits as a health supplement, and they are also used to treat diarrhea, mouth sores, and anti-inflammatory and antibacterial conditions. In the present study, the effects of solvent extractions with methanol (ME group) and 70% ethanol (ET group) on the phytochemicals and antibacterial activity of M. speciosa leaves were examined. In both extract groups, total phenolic content (TPC) and antioxidant activity were measured. In addition, antibacterial activity against Burkholderia sp. was also observed. TPC and TFC levels in the ME group were higher (46.32±2.15 mg GAE/g and 0.351±0.02 mg QE/g, respectively; p≤0.05) than in the ET group (21.14±0.24 mg GAE/g and 0.190±0.02 mg QE/g, respectively). The ME group (IC50 of 270±1.23 µg/mL; p≤0.05) had higher ABTS-antioxidant activity than the ET group (IC50 of 464.4±0.60 µg/mL). Furthermore, the ME group (MIC of 32 µg/mL, p≤0.05) demonstrated inferior antibacterial activity against Burkholderia sp compared to the ET group (MIC of 16 µg/mL, respectively). Overall, the methanol leaf extract of M. speciosa had superior TPC, TFC, and antioxidant activity. Moreover, the 70% ethanol extract demonstrated superior antibacterial activity against the tested pathogen.