ß-secretase 1 inhibitory activity and AMP-activated protein kinase activation of Callyspongia samarensis extracts.

The methanolic extract of Callyspongia samarensis (MCS) significantly inhibited ß-secretase 1 (IC50 99.82 µg/mL) in a dose-dependent manner and demonstrated a noncompetitive type of inhibition. Furthermore, it exhibited the highest AMPK activation (EC50 14.47 µg/mL) as compared with the standard, Aspirin (EC50 >100 µg/mL). HPLC/ESI-MS analysis of MCS extract revealed 15 peaks, in which nine peaks demonstrated similar fragmentation pattern with the known compounds in literature and in database library: 5-aminopentanoic acid (1), 4-aminobutanoic acid (3), Luotonin A (4), (E)-3-(1H-imidazol-5-yl) prop-2-enoic acid (8), Galactosphingosine (10), D-sphingosine (11), 5,7,4'-trihydroxy-3',5'-dimethoxyflavone (12), hydroxydihydrovolide (13), and 3,5-dibromo-4-methoxyphenylpyruvic acid (14); and 6 peaks are not identified (2, 5-7, 9, and 15). Acute oral toxicity test of MCS extract revealed that it is nontoxic, with an LD50 of >2000 mg/kg. Assessment of BBB permeability of MCS extract showed that compound 15 was able to cross the BBB making it a suitable candidate for developing CNS drugs.

Antitubercular constituents from Premna odorata Blanco.

ETHNOPHARMACOLOGICAL RELEVANCE: Premna odorata Blanco (Lamiaceae) is a medicinal plant traditionally used in Albay Province, in southeastern Luzon, Philippines to treat tuberculosis. This study aimed to determine the antitubercular property of the crude extract and sub-extracts of the leaves, and to isolate the bioactive principles from the active fractions. MATERIALS AND METHODS: Through extraction, solvent polarity-based fractionation and silica gel chromatography purification of the DCM sub-extract, compound mixtures from the bioactive fractions were isolated and screened for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv using the colorimetric Microplate Alamar Blue assay (MABA). RESULTS: The crude methanolic extract and sub-extracts showed poor inhibitory activity against Mycobacterium tuberculosis H37Rv (MIC≥128µg/mL). However, increased inhibitory potency was observed for fractions eluted from the DCM sub-extract (MIC=54 to 120µg/mL). Further purification of the most active fraction (MIC=54µg/mL) led to the isolation of a 1-heneicosyl formate (1), 4:1 mixture of ß-sitosterol (2), stigmasterol (3) and diosmetin (4), which were identified through GC-MS analysis (with dereplication) and NMR experiments. The MIC of compound 1 was 8µg/mL. CONCLUSIONS: The results of this study provide scientific basis for the traditional use of Premna odorata as treatment for tuberculosis.