Objective: To isolate and identify the chemical constituents of Ceriops decandra. Methods:The chemical constituents of C. decandra (Griff.) W. Theob. were isolated by silica gel chromatography. The structures of the isolated compounds were identified by nuclear magnetic resonance (NMR) spectroscopy.Results: Chemical investigation of the dichloromethane extracts of the leaves of C. decandra has led to the isolation of 3β-E-coumaroylbetulinic acid (1), lupeol fatty acid esters (2), betulonic acid (3), betulin (4), betulinic acid (5), lupeol (6), lupenone (7), and a mixture of 3β-E-feruloyllupeol (8) and 3β-Z-feruloyllupeol (9), and chlorophyll a (10). The structures of 1-10 were identified by comparison of their NMR data with literature data. Conclusion:To the best of our knowledge, this is the first report on the isolation of 1-3 from C. decandra. Literature search revealed that the triterpenes isolated from C. decandra exhibited anticancer properties.

Examining how seagrass decomposition contributes to trophic pathways in marine ecosystems is crucial in understanding seagrass production. Decomposition rates of seagrasses may depend on many factors such as chemical composition and microbial colonization. In this study, microbial colonization and changes in chemical composition of decomposing material (necromass) of Smooth Ribbon Seagrass, Cymodocea rotundata of Bogtong Bay, Lahuy Island, Caramoan, Philippines were monitored. Seagrass litter were placed in litterbags and incubated in the seagrass meadow in situ for 56 d. Serial dilution, viable plate counts and microbial oxygen consumption analyses were done and gravimetry, Kjeldahl method and acid hydrolysis were used respectively to measure the change in carbohydrate, protein and nitrogen content of the decomposing necromass. Results showed that the decomposition processing rate was 0.27 to 2.51% biomass (g dw) loss per day with a half-life of 2.36 to 2.88 d. Growth of bacteria was greater than fungi throughout the course of experiment. Bacterial abundance (CFU mL-1) fluctuated throughout the experimental period while fungal abundance initially increased but gradually decreased and the initially observed marine fungi ceased to grow in decaying litter until the end of the experiment indicating that heterotrophic bacteria contribute more in the decomposition of seagrass litter. Oxygen consumption as well as protein, lipids and nitrogen content of litter decreased by as over the days of incubation. Therefore, as decomposition proceeds, litter biomass was leached resulting in carbohydrate content loss. But the remaining tissues of decaying C. rotundata were eventually colonized by bacteria and fungi. This further contributes to mineralization of the litter and gradual release of nutrients that could be considered as important trophic inputs to the ecosystem.

Introduction:Cymodocea rotundata Asch. and Schweinf, a widespread seagrass with reported antimicrobial activity, was investigated for its chemical constituents. Methods: The compounds were isolated by silica gel chromatography and identified by NMR spectroscopy. Results: This study has led to the isolation of β-sitosteryl-3β-glucopyranoside-6′-O-fatty acid esters (1), chlorophyll a (2) and a mixture of β-sitosterol (3a) and stigmasterol (3b) in about 1:1 ratio from the dichloromethane extract of C. rotundata. Conclusion: This is the first report on the isolation of 1-3b from C. rotundata. Compounds 2-3b were reported to exhibit antibacterial activity and may be partly responsible for the reported antimicrobial activity of the C. rotundata extract. Key words: Cymodocea rotundata, Cymodoceaceae, β-sitosteryl-3β-glucopyranoside-6′-Ofatty acid esters, Chlorophyll , β-sitosterol, Stigmasterol. Thin layer chromatography was performed with plastic backed plates coated with silica gel F 254 and the plates were visualized by spraying with vanillin/ H 2 SO 4 solution followed by warming. Sample CollectionSamples of the leaves of Cymodocea rotundata Asch. and Schweinf. were collected from the seagrass meadow of Caramoan, Camarines Sur Philippines in September 2016. The samples were authenticated at the Botany Division, Philippine National Museum. General Isolation ProcedureA glass column 6 inches in height and 0.25 inch internal diameter was used for the chromatography. The crude extracts were fractionated by silica gel chromatography using increasing proportions of acetone in CH 2 Cl 2 at 10% increment by volume as eluents. Five milliliter fractions were collected. All fractions were monitored by thin layer chromatography. Fractions with spots of the same Rf values were combined and rechromatographed in appropriate solvent systems until TLC pure isolates were obtained. Final purifications were conducted using Pasteur pipettes as columns. One milliliter fractions were collected. Isolation of the Chemical Constituents from the Leaves of C. rotundataThe air-dried C. rotundata (50 g) leaves were ground in a blender, soaked in CH 2 Cl 2 for 3 days and then filtered. The solvent was evaporated under vacuum to afford a crude extract (0.3 g) which was chromato- Ragasa et al.: Cymodocea rotundataPharmacognosy Journal, Vol 10, Issue 4, Jul-Aug, 2018 621 graphed using increasing proportions of acetone in CH 2 Cl 2 at 10% increment by volume. The 10% acetone in CH 2 Cl 2 fraction was rechromatographed using 10% EtOAc in petroleum ether. The less polar fractions were combined and rechromatographed using 10% EtOAc in petroleum ether to afford 2 (4 mg) after washing with petroleum ether, followed by Et 2 O. The more polar fractions were combined and rechromatographed (2 ×) using 15% EtOAc in petroleum ether to yield a mixture of 3a and 3b (6 mg) after washing with petroleum ether. The 60% acetone in CH 2 Cl 2 fraction was rechromatographed using CH 3 CN:Et 2 O:CH 2 Cl 2 (1:1:8, v/v) to afford 1 (3 mg) after washing with petrole...

No abstract