Subscribe to RSS
DOI: 10.1055/s-0034-1395017
New clerodane diterpenoids from Salvia buchananii Hedge
S. buchananii Hedge (Lamiaceae) (subgenus Calosphace) is a Mexican perennial herbaceous species with almost glabrous petiolate and spathulate leaves and large corollas [1]. The antimicrobial activity of the surface exudate obtained by rinsing the aerial parts of with CH2Cl2 was preliminary evaluated by testing 10µL of 2-fold dilutions (ranging from 1000 mg/L to 64 mg/L) on selected multi-drug-resistant Gram-positive strains, appropriately seeded on agar plates [2]. A clear halo of inhibition was observed on Staphylococcus epidermidis, Staphylococcus aureus (minimum active concentrations for both strains 125 mg/L) and, particularly, on Enterococcus faecium and Enterococcus faecalis (minimum active concentrations for both strains 64 mg/L). The exudate extract, subjected to repeated column chromatography on Sephadex LH-20 and silica gel and to semi-preparative RP-HPLC, yielded two new clerodane diterpenoids (1 and 2), identified by IR and NMR analysis, including TOCSY, COSY, HSQC, HMBC and ROESY experiments, and ESI-TRAP-MS and HR-MS analysis.
Keywords: Salvia buchananii – surface exudate – clerodane diterpenoids – antimicrobial activity
References:
[1] Hedge IC. Tab. 430. Salvia buchananii – Labiatae. In: Curti's Botanical Magazine. Volume CLXXIV. Taylor G. Ed., The Royal Horticultural Society, London; 1963.
[2] Lorian V. Antibiotics in laboratory medicine. Lippincott Williams & Wilkins, Philadelphia, PA, USA; 2005.