Acute and subchronic oral toxicity studies of Nelumbo nucifera stamens extract in rats

Ethnopharmacological relevance

Since the use of Nelumbo nucifera stamens in herbal medicines as well as in cosmetic products are highly prevalent in Thailand and increasing worldwide, acute and subchronic toxicity studies to confirm the safe use of Nelumbo nucifera stamens are warranted.

Aim of the study

Acute and subchronic oral toxicity studies of Nelumbo nucifera stamens extract in rats were performed in the present study in order to evaluate its safety.

Materials and methods

In acute toxicity study, Nelumbo nucifera stamens extract was administered by oral gavage to Sprague-Dawley rats (5 males and 5 females) at a dose of 5000 mg/kg. In subchronic toxicity study, the extract at doses of 50, 100, and 200 mg/kg/day were given orally to groups of rats (6 rats/dose/sex) for 90 consecutive days.

Results

The extract at a dose of 5000 mg/kg produced no treatment-related signs of toxicity or mortality in any of the animals tested during 14 days of the study. In the repeated dose 90-day oral toxicity study, there was no significant difference in body weight between the control and all treatment groups with the exception of the body weight of the female group treated with 200 mg/kg/day of the extract which was statistically significantly less than that of its control counterpart on day 90 but the percent weight changes of both groups were almost similar. Some statistically significant differences in hematological and biochemical parameters as well as in some internal organ weights of both male and female rats treated with the extract at the highest dose were observed. However, no abnormality of internal organs was observed in both gross and histopathological examinations.

Conclusions

These results suggest that the oral lethal dose of Nelumbo nucifera stamens extract for male and female rats is in excess of 5000 mg/kg and the no-observed-adverse-effect level (NOAEL) of the extract for both male and female rats is considered to be 200 mg/kg/day.     

Isolation of a bronchodilator flavonoid from the Thai medicinal plant Clerodendrum petasites

The ethanolic extract of Clerodendrum petasites was tested to evaluate the spasmolytic activity on isolated guinea-pig tracheal smooth muscle. The crude extract (2.25-9.0 mg/ml) dose-dependently caused relaxation of tracheal smooth muscle which was contracted by exposure to histamine. A bioassay-guided fractionation of the crude extract was performed by means of partitioning and centrifugal partition chromatography. Finally the active principle was isolated and identified as the flavonoid hispidulin (EC(50): (3.0+/-0.8)x10(-5) M). These results suggest that hispidulin may be beneficial in the treatment of asthma.     

Larvicidal, adulticidal and repellent effects of Kaempferia galanga

Four fractions of Kaempferia galanga (hexane fraction, dichloromethane fraction 1, dichloromethane fraction 2 and methanolic fraction) were tested for larvicidal activity toward fourth instar Culex quinquefasciatus. The hexane fraction was found to exhibit the highest larvicidal effect with the LC50 of 42.33 ppm. Testing for adulticidal activity, the hexane fraction did not show any promising adulticidal effect. However, it caused a knockdown effect which might be useful as a repellent. It was then tested for repellent activity in human volunteers both in laboratory and field studies. In a laboratory study, the hexane fraction possessed repellency against Aedes aegypti (ED50 value of 30.73 microg/cm2), and provided biting protection for 3 hours. In a field study, it could protect against certain mosquitos, ie, Armigeres subalbatus, Anopheles barbirostris, An. aconitus, Mansonia uniformis, Cx. quinquefasciatus, Cx. gelidus, Cx. tritaeniorhynchus and Ae. aegypti. The hexane fraction did not cause dermal irritation when applied on human skin.     

Anti-inflammatory and antipyretic properties of Clerodendrum petasites S. Moore

The methanol extract from Clerodendrum petasites S. Moore (CP extract) was assessed for anti-inflammatory and antipyretic activities on the experimental animal models. It was found that CP extract possessed moderate inhibitory activity on acute phase of inflammation in a dose-related manner as seen in ethyl phenylpropiolate-induced ear edema (ED(50)=2.34 mg/ear) as well as carrageenin-induced hind paw edema (ED(30)=420.41 mg/kg) in rats. However, CP extract did not elicit any inhibitory effect on arachidonic acid-induced hind paw edema in rats. In subchronic inflammatory model, CP extract provoked a significant reduction of transudation but had no effect on proliferative phase when tested in cotton pellet-induced granuloma model. CP extract also reduced the alkaline phosphatase activity in serum of rats in this animal model. Moreover, CP extract possessed an excellent antipyretic effect when tested in yeast-induced hyperthermic rats. It is postulated that the anti-inflammatory and antipyretic effects of CP extract are caused by the inhibition of the prostaglandin synthesis. Anyhow, CP extract did not possess any analgesic activity in acetic acid-induced writhing response in mice. The results obtained show that C. petasites has beneficial properties since it possesses potent antipyretic and moderate anti-inflammatory activities without ulcerogenic effect.     

Screening for larvicidal activity of ten carminative plants.

Ten species of plants, reported to possess carminative property, were screened for larvicidal potential against Culex quinquefasciatus by exposing early 4th instar larvae to a series of concentrations of the ethanolic extracts of the plants. Mortality counts were made after 24 hours exposure. Probit analysis using computerized Harvard Programming (Hg1, 2) was employed to determine the LC50, LC95 and LC99 values in order to compare the larvicidal potency of the ten plants. Marked larvicidal effects were seen with Kaempferia galanga, Illicium vernum and Spilanthes acmella having LC50 values of 50.54, 54.11 and 61.43 ppm, respectively.     

Quantification of hemoglobin Constant Spring in heterozygote and homozygote by a capillary electrophoresis method

Introduction: Capillary electrophoresis (CE) is a high‐resolution method for detection of hemoglobin Constant Spring (Hb CS). Methods: The levels of Hb CS quantified by CE were compared among three groups of samples including heterozygote and homozygote of Hb CS as well as Hb H‐CS disease classified by DNA molecular diagnosis. The mean corpuscular volume (MCV) of red blood cells was also analyzed among these three groups. Results: Mean ± SD of Hb CS level of the homozygote was not significantly different from that of the Hb H‐CS disease (1.9 ± 1.8 vs. 2.8 ± 1.3, P = 0.13), but it was significantly higher than that of the heterozygote (1.9 ± 1.8 vs. 0.4 ± 0.2, P = 0.007). The MCV <70 fL was found in Hb H‐CS disease only. Conclusion: CE is the preferable method for screening of heterozygote and homozygote of Hb CS. Moreover, in conjunction with a lower MCV (<70 fL), this approach provided a high resolution to identify Hb H‐CS disease.     

Hippocratic screening of ethanolic extracts from two Tabernaemontana species

Ethanolic extracts of roots, stems, leaves and flowers of Tabernaemontana divaricata and T. pandacaqui were studied by an observational (hippocratic) screening method in rats. Extracts of all plant parts caused sedation, decreased respiration and decreased skeletal muscle tone. Except for the leaf extract of T. pandacaqui, the extracts caused vasodilatation of ear vasculature. Analgesic activity was found for all extracts of both Tabernaemontana species, except for the flower extract of T. divaricata. Lethal doses of the extracts caused the animals to die from respiratory paralysis. Intensity of pharmacological activities was greater with the root and stem extracts. The extracts of T. pandacaqui were more potent than those of T. divaricata.     

Hematological alterations and thymic function in newborns of HIV-infected mothers receiving antiretroviral drugs

Objectives

To investigate the effects of antiretroviral (ARV) drugs on hematological parameters and thymic function in HIVuninfected newborns of HIV-infected mothers.

Study design

Cross sectional study.

Setting

Chiang-Mai University Hospital, Chiang-Mai, Thailand.

Participants/Patients

49 HIV-uninfected and 26 HIV-infected pregnancies.

Methods

Cord blood samples of newborns from HIV-uninfected and HIV-infected mothers were collected. Hematological parameters were measured using automatic blood cell count. T-cell receptor excision circles (TRECs) levels in cord blood mononuclear cells (CBMCs), CD4⁺ and CD8⁺ T-cells were quantified using real-time PCR.

Main Outcome Measures

Hemotological parameters and thymic function.

Results

Newborn of HIV-infected mother tended to have lower mean levels of hemoglobin than those of HIV-uninfected mother (137 ± 22 vs 146 ± 17 g/L, P = 0.05). Furthermore, mean of red blood cell (RBC) counts and hematocrit and median of TRECs in CD4+ T-cells in the newborns of the former were significantly lower than those of the latter [3.6 ± 0.7 vs 4.8 ± 0.6 × 10₁₂ cells/L, P <0.001; 0.40 ± 0.07 vs 0.46 ± 0.05 L/L, P <0.001 and 0.53 (IQR: 0.03–5.76) vs 13.20 (IQR: 2.77–27.51) × 10^?3 pg/μL, P = 0.02, respectively].

Conclusion

ARV drugs altered hematological parameters and thymic function (TRECs CD4⁺ T-cells) in HIV-uninfected newborns of HIV-infected mothers.