Immune-stimulating properties of 80% methanolic extract of Ludwigia octovalvis against Shiga toxin-producing E. coli O157:H7 in Balb/c mice following experimental infection.

ETHNOPHARMACOLOGICAL RELEVANCE: Ludwigia octovalvis is an aquatic plant widely distributed throughout the tropical and sub-tropical regions. It is commonly consumed as a health drink and traditionally used for treating various ailments such as dysentery, diarrhea, diabetes, nephritisn and headache. No information is available on its in vivo antibacterial activity against an important foodborne pathogen, Shiga toxin producing Escherichia coli O157:H7. MATERIALS AND METHODS: Male Balb/c mice were orally administered with the extract at doses of 200 or 400mg/kg body weight for one week before the infection with E. coli O157:H7 and continued for 14 consecutive days after infection. Serum antibody (IgA, IgG and IgM) levels were quantified at days 7 and 14 post-challenge by an ADVIA(®) 2400 Clinical Chemistry Auto Analyzer. Nitroblue tetrazolium (NBT) and Ceruloplasmin, as nonspecific immune parameters, were determined enzymatically. RESULTS: A significant increase (p<0.05) in IgA serum level was indicated on the 7th day post-challenge with the pathogen in the experimental group received 400mg/kg of the extract in comparison with other groups. Total IgA serum levels on day 7 post-challenge in groups of PBS negative control, E. coli O157:H7 positive control, E. coli O157:H7+200mg/kg extract group and E. coli O157:H7+400mg/kg extract group were 709.4 ± 149.6, 1655.8 ± 139.7, 1728.6 ± 64.3 and 1971.4 ± 135.6 µg/ml, respectively. Serum IgG and IgM did not significantly change among different groups. The extract administered orally to infected Balb/c mice did not affect the NBT as well as ceruloplasmin levels. CONCLUSIONS: The extract of L. octovalvis contains biologically active principles which increased systemic immune response to E. coli O157:H7 via potentiating the synthesis of IgA antibodies.

Toxicological evaluation of 80% methanol extract of Ludwigia octovalvis (Jacq.) P.H. Raven leaves (Onagraceae) in BALB/c mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Ludwigia octovalvis (Jacq.) P. H. Raven (Family: Onagraceae), as a traditional Malay herbal medicine,has been used to treat gastrointestinal complaints such as diarrhea and dysentery. AIM OF THE STUDY: To date there is no safety information about long term use of Ludwigia octovalvis, a traditionally used medicinal plant in Malaysia. Current study is thus aimed to determine the toxicity profile of the 80% methanolic extract of L. octovalvis by evaluating its acute and subacute toxicity in BALB/c mice. MATERIALS AND METHODS: In the acute toxicity study, a single dose of 5000 mg/kg of the extract was administered orally to six mice (3 males and 3 females). General behaviour, mortality and toxic symptoms were determined daily for 14 days. For the subacute toxicity, four groups of 12 mice of either sex received distilled water (control), 200, 400 and 800 mg/kg of the extract daily for 28 consecutive days by oral gavage. The animals were observed daily for abnormal clinical signs and death. Body weight, relative organ weight, haematological and biochemical parameters of blood as well as heart, kidney, liver, lung and spleen tissues histology were evaluated. RESULTS: In acute and subacute toxicity, the extract did not produce mortality or morbidity. A significant increase (p<0.05) in WBC count and significant decrease in ALT, AST and ALP levels were only observed in males and females that received 400 mg/kg of the extract, while a significant decrease in the cholesterol level was observed at the highest dose (800 mg/kg). Gross examination of liver, kidney, spleen, lung and heart showed normal histological feature. CONCLUSIONS: Repeated administration of L. octovalvis extract at dose levels of 200, 400 and 800 mg/kg/day for 28 consecutive days to male and female mice did not cause any lethality nor produce any toxicological effects. The results suggest that the extract contains biologically active principles which may have immunostimulatory, hepatoprotective and cardiovascular protective properties.