Diligent profiling of preclinical safety of the silk protein sericin

Abstract

BackgroundSericin is a widely used protein in the pharmaceutical industry derived from the silkworm, Bombyx mori, and used for the treatment of various diseases and pathological conditions. It is the main ingredient of the Unani preparation khameera abresham. The study was conducted to evaluate the preclinical toxicity of the silk protein sericin in mice.MethodsIn the acute toxicity study, sericin was administered once orally to different groups of animals at doses of 500, 1000, and 2000 mg/kg. Animals were observed for 14 days. In the sub-acute toxicity study, sericin was administered in mice for 4 weeks in the toxic group at doses of 500, 1000, and 2000 mg/kg, while in the recovery group it was administered for 4 weeks at doses of 500 and 2000 mg/kg followed by 2 weeks of distilled water administration.ResultsIn the acute toxicity study, the observed parameters showed no significant difference, and no mortality was reported. In the sub-acute toxicity study, there were no toxicological effects in any of the estimated parameters, while histopathological analysis showed inflammation in vital organs at the dose of 2000 mg/kg.ConclusionsResults of our acute toxicity study suggest that sericin is safe at all administered doses, while the sub-acute study suggests that the NOAEL (no-observed-adverse-effect level) of sericin is below 2000 mg/kg, at which it can be considered safe.

An exploratory analysis on the toxicity & safety profile of Polyherbal combination of curcumin, quercetin and rutin

“…The body weight was determined on each alternate day throughout the subacute toxicity study by using a digital balance. After the 28 days the animals were sacrificed and all organs were collected, the blood was removed from each organ such as heart, brain, liver, kidney, pancreas, intestine and lungs and weighed each organ on digital balance and the relative organ weight was calculated by formula mentioned below [41].…”

Toxicological evaluation of water-extract sericin from silkworm (Bombyx mori) in pregnant rats and their fetus during pregnancy

“…Sericin was low toxicity in the sub-chronic toxicity study and the NOAEL was estimated to be 1 g/kg/day in SD rats. In another study assessing the acute and sub-acute toxicity of sericin, it was found that orally administered 2000 mg/kg sericin in a single dose did not induce any acute toxicity in mice, while repeatedly administered with 2000 mg/kg for 28 days induced inflammation in brain, small intestine and kidneys of mice (Ahsan et al, 2021). The NOAEL of sericin in mice was suggested to be below 2000 mg/kg in sub-acute study (Ahsan et al, 2021).…”

“…In another study assessing the acute and sub-acute toxicity of sericin, it was found that orally administered 2000 mg/kg sericin in a single dose did not induce any acute toxicity in mice, while repeatedly administered with 2000 mg/kg for 28 days induced inflammation in brain, small intestine and kidneys of mice (Ahsan et al, 2021). The NOAEL of sericin in mice was suggested to be below 2000 mg/kg in sub-acute study (Ahsan et al, 2021). These results indicate that there may be species difference in toxicity of sericin and long term high-dose ingestion of sericin may lead to toxic effects.…”

“…In East Asia, cooked water of silkworm cocoons (mainly sericin) has been widely used to treat diabetes and hypertension. In the Unani system of medicine practiced in south Asia and the Middle East, sericin is extensively used as the main ingredient of various polyherbal formulations in cardiac and neurological related diseases (Khan et al, 2006;Ahsan et al, 2021). With the development of modern medicine, it is found that sericin has rich protein structure and amino acid groups with multiple biological and pharmacological activities, including antioxidant (Kumar and Mandal, 2017), antitumor (Sasaki et al, 2000), anti-inflammatory (Aramwit et al, 2013), anticoagulation, hypoglycemic and cholesterol-lowering activities (Kunz et al, 2016;Dong et al, 2020).…”

Bombyx mori cocoon as a promising pharmacological agent: A review of ethnopharmacology, chemistry, and biological activities

“…On the other hand, in sub-acute toxicity evaluation with the same doses for four weeks, no noticeable toxicological effects were detected, though some inflammation or abnormalities in the crucial organs just at the max dose were reported. Eventually, it was estimated that the NOAEL is below 2000 mg/kg, which can be accounted safe [ 100 ]. Nevertheless, there are some reports regarding adverse effects arising from silk and its ingredients.…”