A.K. Arifah

Screening of microfilaricidal effects of plant extracts against Dirofilaria immitis

Canine dirofilariasis is a common tropical parasitic disease of companion animals, caused by infestation of Dirofilaria immitis filarids within the pulmonary arteries and extending into the right heart. Increased reports of adverse reactions elicited by current microfilaricidal agents against D. immitis such as neurological disorders, circulatory collapse and potential resistance against these agents, warrant the search for new agents in forms of plant extracts. The use of plant extracts in therapeutic medicine is commonly met with scepticism by the veterinary community, thus the lack of focus on its medical potential. This study evaluated the presence of microfilaricidal activities of the aqueous extracts of Zingiber officinale, Andrographis paniculata and Tinospora crispa Miers on D. immitisin vitro at different concentrations; 10mg/ml, 1mg/ml, 100 microg/ml, 10 microg/ml and 1 microg/ml within 24h, by evaluation of relative microfilarial motility as a measure of microfilaricidal activity. All extracts showed microfilaricidal activity with Z. officinale exhibiting the strongest activity overall, followed by A. paniculata and T. crispa Miers. It is speculated that the microfilaricidal mechanism exhibited by these extracts is via spastic paralysis based upon direct observation of the microfilarial motility.

Asiaticoside Inhibits TNF‐α‐Induced Endothelial Hyperpermeability of Human Aortic Endothelial Cells

The increase in endothelial permeability often promotes edema formation in various pathological conditions. Tumor necrosis factor‐alpha (TNF‐α), a pro‐atherogenic cytokine, impairs endothelial barrier function and causes endothelial dysfunction in early stage of atherosclerosis. Asiaticoside, one of the triterpenoids derived from Centella asiatica, is known to possess antiinflammatory activity. In order to examine the role of asiaticoside in preserving the endothelial barrier, we assessed its effects on endothelial hyperpermeability and disruption of actin filaments evoked by TNF‐α in human aortic endothelial cells (HAEC). TNF‐α caused an increase in endothelial permeability to fluorescein isothiocyanate (FITC)‐dextran. Asiaticoside pretreatment significantly suppressed TNF‐α‐induced increased permeability. Asiaticoside also prevented TNF‐α‐induced actin redistribution by suppressing stress fiber formation. However, the increased F to G actin ratio stimulated by TNF‐α was not changed by asiaticoside. Cytochalasin D, an actin depolymerizing agent, was used to correlate the anti‐hyperpermeability effect of asiaticoside with actin cytoskeleton. Surprisingly, asiaticoside failed to prevent cytochalasin D‐induced increased permeability. These results suggest that asiaticoside protects against the disruption of endothelial barrier and actin rearrangement triggered by TNF‐α without a significant change in total actin pool. However, asiaticoside seems to work by other mechanisms to maintain the integrity of endothelial barrier rather than stabilizing the F‐actin organization. Copyright

Rapid spectrophotometric determination, characterization and anti-inflammatory efficacy evaluation of nanoencapsulated diclofenac sodium

This study was aimed to develop a simple and reproducible spectrophotometric method for the characterization of diclofenac sodium (DS) and to evaluate the efficacy of orally administered liposome encapsulated as well as free form DS in animal model. A simple, rapid and economical spectrophotometric analytical procedure with estimation in UV-visible region was performed on DS using dimethyl sulfoxide as solvent. Parameters such as time, temperature and types of solvent were studied for 20 μg/mL DS solution at 295 nm. All parameters and results of analysis were statistically validated. Liposome-encapsulated and free form DS samples were subjected to characterization study that includes entrapment efficacy determination and particle size analysis. Drug samples were further tested for their in vivo anti-inflammatory efficacy using histamine-induced paw edema test. Under optimized parameters, the Beer’s law is obeyed in range of 0.625-40 μg/mL at λmax 295 nm. A linear working range of 5-35 μg/mL with regression coefficient of 0.9978 was obtained by using seven triplicate analyses of drug samples at seven different concentrations. The limit of detection and limit of quantitation was 1.19 and 3.62 μg/mL, respectively. Result of characterization study showed that the optimum formulation, which has high entrapment efficacy of 87 %, homogenous in size (polydispersity index 0.27), stable and reproducible, were obtained by using the Pro-Lipo Duo with 10 h hydration time and 16 mg/g DS. The liposome encapsulated DS resulted in significant (P

In vivo antitrypanosomal activity of Garcinia hombroniana aqueous extract.

The anti-Trypanosoma evansi activity of Garcinia hombroniana (seashore mangosteen) leaves aqueous extract was tested on experimentally infected Sprague-Dawley rats. Treatment of infected rats with G. hombroniana extract resulted in a significantly extended post-infection longevity (p < 0.05), compared to the untreated control group. The possible mode of antitrypanosomal effect of the plant extract was also investigated on cultured T. evansi in HMI-9 medium with the addition of 25 µg/ml G. hombroniana aqueous extract. It was observed that the addition of G. hombroniana extract resulted in the inhibition of trypanosomal kinetoplast division, with no significant inhibitory effect on nuclear division. It is concluded from the current study that the aqueous extract of G. hombroniana has a potential antitrypanosomal activity through the inhibition of kinetoplast division, as one of the possible mechanisms of its antitrypanosomal effect. This plant could serve as a possible source of new antitrypanosomal compounds.

Analgesic activity of three Channa spp. fish extracts

In the present study, three Malaysian Channa spp. fish Channa striatus, Channa micropeltes and Channa lucius were assessed for their analgesic activity. Distilled water and mixture of chloroform: methanol were used for extraction. The analgesic or antinociceptive activity was investigated by abdominal writhing and hot plate test. The water extract of Channa striatus and the chloroform: methanol extract Channa lucius produced potent antinociceptive effect when assessed with the abdominal writhing test. The activity was compared to morphine where the activity of the extracts was less potent than the opioid. In the hote plate test, water extract of Channa striatus revealed significant activity and chloroform:methanol extract of Channa micropeltes had moderate activity. However, these activities were statistically lower than morphine. Collectively, this study also showed that Channa striatus extract was more potent analgesic agent when compared to the other closely related snakehead Channa micropeltes and Channa lucius.