Bioactivity of compounds secreted by symbiont bacteria of Nudibranchs from Indonesia

The aims of this work are to isolate bacterial symbionts from nudibranchs and subsequently to determine anti-Methicillin resistant (MRSA), cytotoxicity and anti-Herpes simplex virus type 1 (HSV-1) activities of bio compounds. A total of 15 species of nudibranchs were collected from Karimunjawa and five species from Bali, respectively. A total of 245 bacteria isolates were obtained. The anti-MRSA activity screening activity indicated two active bacteria. Ethyl acetate extracts from supernatants, indicating extracelullar compounds, showed an inhibition zone against MRSA at concentrations of 500-1,000 µg/ml. DNA sequence analysis showed that the strain KJB-07 from was closely related to , whereas the strain NP31-01 isolated from was closely related to . The extract of was cytotoxic to Vero cells at a concentration of 75 µg/ml. The extract of presented no cytotoxicity at concentrations of 5-1,000 µg/ml. No anti HSV-1 was observed for both isolated bacteria. This is the first study describing research on anti-MRSA, cytotoxicity and anti HSV-1 activity of bacterial symbionts from the viscera of nudibranch. Compounds produced by and , had potential anti-MRSA activity. However, only extracts from showed cytotoxic effects on Vero cells. Three compounds were identified by LC/MS after purification from culture supernatant.