Hydroxybenzoic acid derivative, dibenzofuran and ergostane-type metabolites from Ramalina nervulosa

• Main Author: San Pedro, Zenaida V.
• Format: text
• Language: English
• Published: Animo Repository 2002
• Subjects: Lichens; Plant metabolites; Acids; Derivatization; Extracts; Medicinal-Pharmaceutical Chemistry
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/2987
• Institution: De La Salle University

Ramalina nervulosa samples collected from Tagaytay and Tartaria, Cavite was studied to determine the secondary metabolites present and their bioactivity.The pure isolates RNC25 and RNC52 from the crude chloroform extract were identified as usnic acid (16) and methyl B-orsellinate (7) respectively. MS data of isolate RNC42 showed two major components. The MS fragments were characteristic of ergosterol derivatives. A fragment of m/z 255 indicated the presence of two double bonds while m/z 253 for the presence of three double bonds. The 1H NMR and 13C NMR data showed that the major components are ergosta-5, 7, 22-trien-3-ol (29) and ergosta-5,22-dien-3-ol (31).The 1H NMR and 13c NMR data of major component of isolate RNH42 showed that the compound was also ergosta-5,7,22-trien-3-ol (29). This isolate was found to be active against pathogenic microorganisms and yeast causing skin infections. Usnic acid (16) was found to be non-toxic (ALD 16g/kg) at the dosage tested and caused increase in the systolic and diastolic pressure of rats. The lichen thallus possesses significant antibacterial, anti-inflammatory and anticancer activities.