||Clinacanthus nutans (Family: Acanthaceae) or locally known as “Sabah snake grass” in Malaysia, is used for the
treatment of herpes simplex infection, herpes zoster infection, diabetes mellitus, skin rash, dysuria and cancer. The
objective of this study was to evaluate the safety of methanol leaves extract of C. nutans by sub-acute 28-day
(repeated doses) oral administration to male Sprague Dawley (SD) rats. First group was orally treated with distilled
water and served as control (n=6), whereas the remaining treatment groups (n=6) were orally treated with a single
dose daily of 300 mg/kg, 600 mg/kg and 900 mg/kg of C. nutans extract, respectively for 28 days. Cage-side
observations were done daily. The animal body weight, food consumption and water intake were recorded weekly.
Blood was collected via cardiac puncture on day-29 and used to perform biochemical analyses, i.e. liver function
tests, kidney function tests, total protein, glucose, lipid profile and haematology evaluation. The relative organ
weights were also measured. All results were expressed as mean ± standard deviation and analysed using Dunnett’s
test. From the results obtained, repeated oral administration of methanol leaves extract of C. nutans (300 mg/kg, 600
mg/kg and 900 mg/kg) for 28 days did not cause mortality or adverse effects in rats. No significant change was
observed in the body weight changed, water and food intake between the treatment group and control group.
However, significant increase in serum total proteins (p<0.01), albumin/globulins ratio (p<0.01) and relative liver
weight (p<0.01) were observed in male rats after 28 days treatment with 900 mg/kg of C. nutans. In conclusion, 28
days oral administration of methanol leaves extract of C. nutans up to 900 mg/kg was safe in male SD rats without
causing any adverse effects. The Non-Observable-Adverse-Effect-Level (NOAEL) for sub-acute (28 days) effects of
methanol leave extract of C. nutans in male SD rats was 900 mg/kg bw.