Hazrina Hazni

Antidiabetic and Antioxidant Properties of Alkaloids from Catharanthus roseus (L.) G. Don.

Catharanthus roseus (L.) G. Don is a herbal plant traditionally used by local populations in India, South Africa, China and Malaysia to treat diabetes. The present study reports the in vitro antioxidant and antidiabetic activities of the major alkaloids isolated from Catharanthus roseus (L.) G. Don leaves extract. Four alkaloids—vindoline I, vindolidine II, vindolicine III and vindolinine IV—were isolated and identified from the dichloromethane extract (DE) of this plant’s leaves. DE and compounds I–III were not cytotoxic towards pancreatic β-TC6 cells at the highest dosage tested (25.0 µg/mL). All four alkaloids induced relatively high glucose uptake in pancreatic β-TC6 or myoblast C2C12 cells, with III showing the highest activity. In addition, compounds II–IV demonstrated good protein tyrosine phosphatase-1B (PTP-1B) inhibition activity, implying their therapeutic potential against type 2 diabetes. III showed the highest antioxidant potential in ORAC and DPPH assays and it also alleviated H2O2-induced oxidative damage in β-TC6 cells at 12.5 µg/mL and 25.0 µg/mL.

Gastroprotective Activity of Polygonum chinense Aqueous Leaf Extract on Ethanol-Induced Hemorrhagic Mucosal Lesions in Rats

Polygonum chinense is a Malaysian ethnic plant with various healing effects. This study was to determine preventive effect of aqueous leaf extract of P. chinense against ethanol-induced gastric mucosal injury in rats. Sprague Dawley rats were divided into seven groups. The normal and ulcer control groups were orally administered with distilled water. The reference group was orally administered with 20 mg/kg omeprazole. The experimental groups received the extracts 62.5, 125, 250, and 500 mg/kg, accordingly. After sixty minutes, distilled water and absolute ethanol were given (5 mL/kg) to the normal control and the others, respectively. In addition to histology, immunohistochemical and periodic acid schiff (PAS) stains, levels of lipid peroxidation, malondialdehyde (MDA), antioxidant enzymes, and superoxide dismutase (SOD) were measured. The ulcer group exhibited severe mucosal damages. The experimental groups significantly reduced gastric lesions and MDA levels and increased SOD level. Immunohistochemistry of the experimental groups showed upregulation and downregulation of Hsp70 and Bax proteins, respectively. PAS staining in these groups exhibited intense staining as compared to the ulcer group. Acute toxicity study revealed the nontoxic nature of the extract. Our data provide first evidence that P. chinense extract could significantly prevent gastric ulcer.

Vindogentianine, a Hypoglycemic Alkaloid from Catharanthus roseus (L.) G. Don (Apocynaceae)

Vindogentianine, a new indole alkaloid together with six known alkaloids, vindoline, vindolidine, vindolicine, vindolinine, perivine and serpentine were isolated from leaf extract (DA) of Catharanthus roseus (L.) G. Don. Their structures were elucidated by spectroscopic methods; NMR, MS, UV and IR. Vindogentianine is a dimer containing a vindoline moiety coupled to a gentianine moiety. After 24h incubation, vindogentianine exhibited no cytotoxic effect in C2C12 mouse myoblast and β-TC6 mouse pancreatic cells (IC50>50μg/mL). Real-time cell proliferation monitoring also indicated vindogentianine had little or no effect on C2C12 mouse myoblast cell growth at the highest dose tested (200μg/mL), without inducing cell death. Vindogentianine exhibited potential hypoglycemic activity in β-TC6 and C2C12 cells by inducing higher glucose uptake and significant in vitro PTP-1B inhibition. However, in vitro α-amylase and α-glucosidase inhibition assay showed low inhibition under treatment of vindogentianine. This suggests that hypoglycemic activity of vindogentianine may be due to the enhancement of glucose uptake and PTP-1B inhibition, implying its therapeutic potential against type 2 diabetes.

Alkaloids from Fissistigma latifolium (Dunal) Merr

A phytochemical study of the bark of Fissistigma latifolium (Annonaceae) yielded a new aporphine alkaloid, (-)-N-methylguattescidine (1), and eight known alkaloids: liriodenine (2), oxoxylopine (3), (-)-asimilobine (4), dimethyltryptamine (5), (-)-remerine (6), (-)-anonaine (7), columbamine (8) and lysicamine (9). The compounds were isolated using various chromatographic methods and structural elucidation was accomplished by means of spectroscopic methods, notably 1D-NMR (1H, 13C, DEPT), 2D-NMR (COSY, HMQC, HMBC), UV, IR and MS.

Cytotoxic and Antioxidant Compoundsfrom the Stem Bark of Goniothalamus tapisoides Mat Salleh

Eleven compounds: goniomicin A (1), goniomicin B (2), goniomicin C (3), goniomicin D (4), tapisoidin (5), goniothalamin (6), 9-deoxygoniopypyrone (7), pterodondiol (8), liriodenine (9), benzamide (10) and cinnamic acid (11), were isolated from the stem bark of Goniothalamus tapisoides. All compounds were identified by spectroscopic analysis and, for known compounds, by comparison with published data. Goniothalamin (6) exhibited mild cytotoxic activity towards a colon cancer cell line (HT-29), with an IC50 value of 64.17 ± 5.60 µM. Goniomicin B (2) give the highest antioxidant activity in the DPPH assay among all compounds tested, with an IC50 of 0.207 µM.

Neonaucline, a new indole alkaloid from the leaves of Ochreinauclea maingayii (Hook. f.) Ridsd. (Rubiaceae).

A new indole alkaloid; neonaucline (1), along with six known compounds–Cadamine (2), naucledine (3), harmane, benzamide, cinnamide and blumenol A–were isolated from the leaves of Ochreinauclea maingayii (Rubiaceae). In addition to that of compound 1, 13C-NMR data of cadamine (2) and naucledine (3) were also reported. Structural elucidations of these alkaloids were performed using spectroscopic methods especially 1D- and 2D-NMR, IR, UV and LCMS-IT-TOF. The excellent vasorelaxant activity on isolated rat aorta was observed for the alkaloids 1–3 after injection of each sample at 1 × 10−5 M.

Lancifoliaine, a New Bisbenzylisoquinoline from the Bark of Litsea lancifolia

A new bisbenzylisoquinoline, lancifoliaine (1), together with seven known alkaloids – N-allyllaurolitsine (2), reticuline (3), actinodaphnine, norboldine, pallidine, cassythicine and boldine – were isolated from the stem bark of Litsea lancifolia (Lauraceae). In addition to that of lancifoliaine, complete 13C-NMR data of N-allyl-laurolitsine (2) was also reported. The alkaloidal structures were elucidated by means of high field 1D- and 2D-NMR IR, UV, and LCMS-IT-TOF spectral data. N-Allyllaurolitsine (2) showed a moderate vasorelaxant activity on isolated rat aorta.

Rauniticine-allo-oxindole B methanol monosolvate.

The title pentacyclic oxindole alkadoid, isolated from Uncaria longiflora, crystallizes as a methanol solvate, C20H22N2O4·CH4O. The five-membered ring comprising the indole fused ring is nearly planar [maximum atomic deviation = 0.031 (2) Å], whereas the five-membered ring having alphatic C atoms adopts an envelope shape (with the tertiary N atom representing the flap). The six-membered ring that shares an N atom with the envelope-shaped ring adopts a chair shape; the six-membered ring having an O atom is sofa-shaped. The carboxylic acid group acts as a hydrogen-bond donor to a methanol molecule; this, in turn, acts as a hydrogen-bond donor to the double-bond carboxyl O atom of an adjacent molecule, generating a chain. Adjacent chains are linked by N—H⋯O hydrogen bonds, forming a layer motif.

Flavokavain B from the rhizome of Alpinia mutica Roxb

The title compound [systematic name: (E)-1-(2-hydroxy-4,6-dimethoxyphenyl)-3-phenylprop-2-en-1-one], C17H16O4, has an aromatic ring at both ends of the –CH= CH–C(=O)– fragment with the –CH=CH– bond in a trans configuration. The phenyl ring is nearly coplanar with this fragment [dihedral angle 4.8 (3) °] as is the hydroxyldimethoxylphenyl unit [dihedral angle 6.3 (3) °]. The hydroxy group is the donor in an intramolecular hydrogen bond to the double-bonded O atom.

3-Acetyl-5-hy-droxy-2-methyl-anthra[1,2-b]furan-6,11-dione.

The asymmetric unit of the title compound, C19H12O5, contains two independent molecules, both slightly buckled along an axis passing through the C=O bonds of the anthraquinone ring system (r.m.s. deviation of non-H atoms = 0.082 and 0.148 Å): the benzene rings are twisted to each other by 4.3 (3)°in one molecule and 10.6(3)° in the other. In both molecules, the hydroxy group forms an intramolecular O—H⋯O hydrogen bond. The two independent molecules interact by π–π stacking with a centroid–centroid distance of 3.539 (2) Å between hydroxybenzene rings of adjacent molecules.