Safety assessment of the aqueous extract of the flowers of Nymphaea lotus Linn (Nymphaeaceae): Acute, neuro- and subchronic oral toxicity studies in albinos Wistar rats

Abstract

Background Nymphaea lotus Linn (N. lotus) is a medicinal plant widely used in Cameroon popular medicine, to treat neuropsychiatric conditions, male sexual disorders or as food supplement. However, scientific data on the pharmacotoxic profile of this plant are not available. The safety of N. lotus was assessed in acute, neuro- and subchronic toxicity studies by following the OECD guidelines. Effectively, no data have been published until now in regard to its safety on the nervous system. Methods Aqueous extract of N. lotus at doses of 200, 400 and 600 mg/kg body weight (BW) was evaluated for nitrites contents and orally administered to rats daily for 28 days (5 male, 5 female per group). The control group received distilled water (10 mL/kg) and a satellite group was used to observe reversal effects. Neurotoxicity of the plant was determined using open field test for motor coordination, ataxia and gait analysis. Clinical signs and state of livelihood were recorded during the 24 h, then for 28 days of treatments. At the end of 28-day period, animals were anesthetized and decapitated. The whole brain was homogenized for neurobiochemical analysis. Blood samples were collected with or without anticoagulant for hematological examinations and serum analysis. Specimens of liver, kidney, testis, ovaries, and brain were fixed in 10 % formalin and processed for histopathological examinations. Results Our findings indicate dose-dependent elevation of nitrites contents in the flowers aqueous extract of N. lotus. Acute toxicity study revealed no signs of toxicity neither at the dose 2,000 mg/kg nor at 5,000 mg/kg. Thus the LD50 value of aqueous extract of N. lotus flowers is superior to 5,000 mg/kg. The repeated administration of N. lotus during 28 days, induced no signs of neurobehavioral changes in male, but female rats exhibited dose-dependent response in the open field test, suggesting sex and dose-relative psychotropic effects of N. lotus. The evaluation of neurobiochemistry revealed consistent rise of brain cholesterol by 44.05 %; 158.10 % and 147.62 % respectively in male rats treated with the doses of 200, 400 and 600 mg/kg. In female rats, these levels were significantly increased (p<0.001) only at the dose of 600 mg/kg compared to control. This trend persisted after 14 days withdrawal. Brain potassium and calcium concentrations were increased in all rats compared to their respective control receiving distilled water, suggesting transmembrane current stabilizing properties of brain cells by our extract. Further, serum biochemical analysis demonstrated that 28-day administration of N. lotus flowers increased depending on the dose and sex, the levels of serum urea, proteins, creatinine and bilirubin and reduced γ-glutamyltransferase (GGT) and alkaline phosphatase (ALP) activities. These results suggest liver alterations that are endowed by lower liver relative weight and histology damages observed in female rats treated with the dose of 600 mg/kg of our extract. We also observed a rise in the low-density lipoprotein (LDL...

Enrichment in Antioxidant Flavonoids of Stamen Extracts from Nymphaea lotus L. Using Ultrasonic-Assisted Extraction and Macroporous Resin Adsorption

“…Many research teams have conducted studies focusing on N. lotus in several aspects. The safety of N. lotus flower extracts was verified by Kameni et al [10]. Acute, sub-chronic and neurotoxicity were studied in vivo using an albinos Wistar rat model.…”

“…Acute, sub-chronic and neurotoxicity were studied in vivo using an albinos Wistar rat model. This study indicated that the N. lotus flowers extract probably account for neuroprotective, immune-boosting and antioxidant activity without neurotoxicity [10]. Furthermore, the pharmacological and medicinal potential of this medicinal species were currently confirmed at in vivo level, i.e., anti-diarrhea effect of N. lotus rhizome extract [5], anxiolytic and antidepressant potential from the N. lotus leaf extract [11].…”

A Cosmetic Perspective on the Antioxidant Flavonoids from Nymphaea lotus L.

“…In Egypt, Thailand, Indonesia and a large number of Asian countries, almost every part of N. lotus has long been consumed as a vegetable [3,5,[7][8][9]13,[15][16][17]. As an important ingredient for formulating Asian traditional medicines, particularly for circulatory system syndrome, several parts of this plant, such as root, leaves and flower parts, have been used since ancient times [1,7,13].…”

“…We may observe that much of the cosmetic potential of this plant is primarily based on its high accumulation of flavonoids, mostly in its flower parts [5,6,11]. In addition, many studies have confirmed its toxicological safety, which is a good argument for future applications [7,10,13,18].…”

“…Almost every part of this plant, such as rhizome, stolon, petiole, young leaves, peduncle and flower, has long been eaten as fresh vegetables or as a cooking ingredient in a variety of healthy menus [3,5]. In addition, a huge number of studies have reported on its medicinal potential to cure a number of diseases, and its extracts are used in traditional medicines in many countries in Asia and Africa [6][7][8][9][10][11][12][13]. Its cosmetic potential has also been reported [5].…”