Hanita Omar

Anti-ulcerogenic effect of methanolic extracts from Enicosanthellum pulchrum (King) Heusden against ethanol-induced acute gastric lesion in animal models.

A natural source of medicine, Enicosanthellum pulchrum is a tropical plant which belongs to the family Annonaceae. In this study, methanol extract from the leaves and stems of this species was evaluated for its gastroprotective potential against mucosal lesions induced by ethanol in rats. Seven groups of rats were assigned, groups 1 and 2 were given Tween 20 (10% v/v) orally. Group 3 was administered omeprazole 20 mg/kg (10% Tween 20) whilst the remaining groups received the leaf and stem extracts at doses of 150 and 300 mg/kg, respectively. After an additional hour, the rats in groups 2–7 received ethanol (95% v/v; 8 mL/kg) orally while group 1 received Tween 20 (10% v/v) instead. Rats were sacrificed after 1 h and their stomachs subjected to further studies. Macroscopically and histologically, group 2 rats showed extremely severe disruption of the gastric mucosa compared to rats pre-treated with the E. pulchrum extracts based on the ulcer index, where remarkable protection was noticed. Meanwhile, a significant percentage of inhibition was shown with the stem extract at 62% (150 mg/kg) and 65% (300 mg/kg), whilst the percentage with the leaf extract at doses of 150 and 300 mg/kg was 63% and 75%, respectively. An increase in mucus content, nitric oxide, glutathione, prostaglandin E2, superoxide dismutase, protein and catalase, and a decrease in malondialdehyde level compared to group 2 were also obtained. Furthermore, immunohistochemical staining of groups 4–7 exhibited down-regulation of Bax and up-regulation of Hsp70 proteins. The methanol extract from the leaves and the stems showed notable gastroprotective potential against ethanol.

Aporphine Alkaloids from the Leaves of Phoebe grandis (Nees) Mer. (Lauraceae) and Their Cytotoxic and Antibacterial Activities

The oxoaporphine alkaloid lysicamine (1), and three proaporphine alkaloids, litsericinone (2), 8,9,11,12-tetrahydromecambrine (3) and hexahydromecambrine A (4) were isolated from the leaves of Phoebe grandis (Nees) Merr. (Lauraceae). Compounds 2 and 3 were first time isolated as new naturally occurring compounds from plants. The NMR data for the compounds 2–4 have never been reported so far. Compounds 1 and 2 showed significant cytotoxic activity against a MCF7 (human estrogen receptor (ER+) positive breast cancer) cell line with IC50 values of 26 and 60 µg/mL, respectively. Furthermore, in vitro cytotoxic activity against HepG2 (human liver cancer) cell line was evaluated for compounds 1–4 with IC50 values of 27, 14, 81 and 20 µg/mL, respectively. Lysicamine (1) displayed strong antibacterial activity against Bacillus subtilis (B145), Staphylococcus aureus (S1434) and Staphylococus epidermidis (a clinically isolated strain) with inhibition zones of 15.50 ± 0.57, 13.33 ± 0.57 and 12.00 ± 0.00 mm, respectively. However, none of the tested pathogenic bacteria were susceptible towards compounds 2 and 3.

N-Cyanomethylnorboldine: A New Aporphine Isolated from Alseodaphne perakensis (Lauraceae)

A phytochemical study of the bark of Alseodaphne perakensis has yielded three aporphine alkaloids: the new compound N-cyanomethylnorboldine (1), and the two known alkaloids N-methyllaurotetanine (2) and norboldine (3). The isolation was achieved by chromatographic techniques and the structural elucidation was performed via spectral methods, notably 1D- and 2D-NMR, UV, IR, and HRFABMS. The vasorelaxation activity of compound 1 has been studied.

(+)-N-(2-Hydroxypropyl)lindcarpine: A New Cytotoxic Aporphine Isolated from Actinodaphne pruinosa Nees

One new alkaloid; (+)-N-(2-hydroxypropyl)lindcarpine (1), together with four known aporphine alkaloids, (+)-boldine (2) (+)-norboldine (3), (+)-lindcarpine (4) and (+)-methyllindcarpine (5) were isolated from the stem bark of Actinodaphne pruinosa Nees (Lauraceae). (+)-N-(2-Hydroxypropyl)lindcarpine (1) exhibited cytotoxic activity against P-388 murine leukemia cells with an IC50 value of 3.9 μg/mL. Structural elucidation of all the compounds were performed by spectral methods such as 1D- and 2D- NMR, IR, UV, and HRESIMS.

Methanol leaf extract of actinodaphne sesquipedalis (Lauraceae) enhances gastric defense against ethanol-induced ulcer in rats

Actinodaphne sesquipedalis Hook. F. Var. Glabra (Kochummen), also known as “Medang payung” by the Malay people, belongs to the Lauraceae family. In this study, methanol leaf extract of A. sesquipedalis was investigated for their acute toxicity and gastroprotective effects to reduce ulcers in rat stomachs induced by ethanol. The rats were assigned to one of five groups: normal group (group 1), ulcer group (group 2), control positive drug group (group 3) and two experimental groups treated with 150 mg/kg (group 4) and 300 mg/kg (group 5) of leaf extract. The rats were sacrificed an hour after pretreatment with extracts, and their stomach homogenates and tissues were collected for further evaluation. Macroscopic and histological analyses showed that gastric ulcers in rats pretreated with the extract were significantly reduced to an extent that it allowed leukocytes penetration of the gastric walls compared with the ulcer group. In addition, an ulcer inhibition rate of >70% was detected in rats treated with both doses of A. sesquipedalis extract, showing a notable protection of gastric layer. Severe destruction of gastric mucosa was prevented with a high production of mucus and pH gastric contents in both omeprazole-treated and extract-treated groups. Meanwhile, an increase in glycoprotein uptake was observed in pretreated rats through accumulation of magenta color in Periodic Acid Schiff staining assay. Analysis of gastric homogenate from pretreated rats showed a reduction of malondialdehyde and elevation of nitric oxide, glutathione, prostaglandin E2, superoxide dismutase and protein concentration levels in comparison with group 2. Suppression of apoptosis in gastric tissues by upregulation of Hsp70 protein and downregulation of Bax protein was also observed in rats pretreated with extract. Consistent results of a reduction of gastric ulcer and the protection of gastric wall were obtained for rats pretreated with A. sesquipedalis extract, which showed its prominent gastroprotective potential in rats’ stomach against ethanol-induced ulcer.

DECLININE: THE NEW ALKALOID FROM PHOEBE DECLINATA NEES

The new alkaloid named as declinine had been isolated from stem bark of Phoebe declinata Nees (Lauraceae). T h is alkaloid had been obtained for the first time from this plant. The structure of declinine was determined by spectroscopic analysis of 1D and 2D NMR, IR, UV, and LCMS. Declinine exhibited good antioxidant activity by DPPH assay with an IC 50 value 11.8 µg/mL compared to boldine as a standard with an IC 50 value 5.8 µg/mL.

Antibacterial and Antioxidant Activities from the Extracts of the Leaves ofPhoebe Grandis (Nees) Merr

The genus of Phoebe of family Lauraceae is found the most abundance in Borneo and the Malaysian Peninsular. Phoebe grandis locally known as ‘medang ketanah or tanah.’ The isolation of three compounds lysicamine (1), N-methyllitsericinone (2), N-methyllitsericine (3) were evaluated against selected pathogenic bacteria which are Staphylococcus epidermidis, Staphylococcus aureus, Bacillus, Pasteurella multocida and Enterobacter cloacae. Lysicamine (1) showed strong antibacterial activity against all bacteria strains. (The result will be highlighted during the presentation). Meanwhile, the biological screening of antioxidant activities were determined using DPPH scavenging and ferric reducing antioxidant power (FRAP) assays. The present study of the hexane, dichloromethane, methanol and alkaloid extracts from the leaves of Phoebe grandis showed these extracts had good scavenging activity. The antioxidant activity gave potent result to the alkaloids extract compared to other extracts.