Toxicity study of Chlorella vulgaris water extract on female Sprague Dawley rats by using the Organization for Economic Cooperation and Development (OECD) Guideline 420

Abstract

Chlorella vulgaris, a coccoid green eukaryotic microalga, is a popular food supplement and has been marketed as a nutritional supplement in Asia. Despite numerous reports on the antioxidant property of this species, its toxic effect has not been extensively studied. The aim of this study was to determine the acute oral toxic effect of C. vulgaris on female Sprague Dawley (SD) rats. An acute oral toxicity assessment of C. vulgaris was performed based on the Organization for Economic Cooperation and Development (OECD) Guideline 420. These guidelines are divided into a sighting study and a main study. In the sighting study, C. vulgaris extract was administered orally in sequential doses of 5, 50, 300 and 2000 mg kg−1 body weight (BW) with one rat used for each dosage. Clinical observation and mortality were observed for each rat to monitor signs of toxicity for 14 days. BW and relative organ weight (ROW) were recorded. Blood was collected for liver function test (LFT). Gross pathological evaluations were performed after euthanasia of rats. Haematoxylin and eosin (H&E) staining of the liver and kidney was also performed. The main study was performed based on the highest dose in the sighting study that did not exhibit any signs of toxicity and mortality. For 14 days, clinical observations, BW, and ROW were recorded. Blood from rats in the main study was also measured for LFT, and gross pathological evaluations and H&E staining of the liver and kidney were also performed. The highest dose of 2000 mg kg−1 BW C. vulgaris was used in the main study. No toxicity and mortality were observed in both the sighting study and the main study. Increases in BW were observed in both studies. Gross pathological evaluations showed no signs of organ abnormalities on each organ in the sighting and main studies. The ROW also showed no differences. The values of biochemical parameters in the liver function test showed no differences in the sighting study. However, in the main study, significant decreases in alkaline phosphatase (ALP) and aspartate aminotransferase (AST) were observed on day 14 compared with day 0 (p < 0.05). Chlorella vulgaris showed no toxicity at the dose of 2000 mg kg−1 BW. In conclusion, C. vulgaris can be categorized as unclassified according to the Globally Harmonised Classification System (GHS) for chemical substances and mixtures.

Chlorella vulgaris Ameliorates Oxidative Stress and Improves the Muscle Regenerative Capacity of Young and Old Sprague-Dawley Rats

“…No significant difference was observed in the relative organ weight of the heart, brain, and muscle for all young groups treated with C. vulgaris, suggesting that no toxicity of C. vulgaris occurred. A previous study also reported no toxicity or mortality in female SD rats treated with C. vulgaris by using the Organization for Economic Cooperation and Development (OECD) Guideline 420 [36]. However, a significant decrease in the liver and kidney relative organ weight was observed in the control old rats and the old rats treated with C. vulgaris compared to the control young rats.…”

In vivo Investigation to Validate the Traditional Usage of Sorbaria tomentosa (Lindley) Reh. Root Extract against Alloxan-induced Diabetic Rats

“…The OECD guideline number 420 was followed in conducting the acute oral toxicity test. [10] Significant (p≤0.05) increases in bw and decreases in BGL were seen in the treatment groups following dosage of the ethanolic root extract of ST (50 mg/kg of Bw) and the common medication glibenclamide 5 mg/kg of bw) as shown in Tables 1 and 2.…”

Toxicity evaluation induced by single and 28-days repeated exposure of withametelin and daturaolone in Sprague Dawley rats

“…Weight differences are influenced by several factors such as growth hormone and somatostatin changes in hormone status as seen in sexual steroid secretion which influence maturation patterns and subsequential changes in neurotransmitters affecting food consumption. Furthermore, the rat environment and type of treatment can also be stressful for rat, resulting in weight changes ( Zainul Azlan et al, 2020 ). Changes in weight are considered to be indicators of adverse reactions caused by chemical components.…”