The Potential Use of Kratom in Coronavirus Disease (COVID-19)
The objective is to assess the potential of Kratom (Mitragyna speciosa) in COVID-19 based on the following:
- Efficacy: Focus on antiviral (viral disease & conditions) or immunomodulatory and possible mechanism/s of kratom with either effect
- Safety of kratom
Electronic databases were searched using pre-determined terminologies such as ‘mitragyna speciosa’, ‘antiviral’, immunomodulatory’, ‘immune response’, ‘mechanism of action’, and ‘safety’. All clinical and preclinical studies (both in vitro and in vivo) related to safety and efficacy or effectiveness of probiotics in treating viral diseases were included.
Results and discussion:
- Currently, there is no scientific evidence (in vitro, in vivo, and clinical) published on the antiviral activity of kratom or its related compounds
- Two in vitro studies studied the anti-inflammatory mechanism of Mitragynine and supercritical fluid extract of Kratom leaves. The first study showed that Mitragynine can significantly reduce cyclooxygenase (COX)-2 expression in lipopolysaccharide (LPS)-treated macrophage cells while another study showed that Kratom leaves extracted by supercritical fluid inhibits nitric oxide (NO) activity using Griess assay. Only one animal study showed that the methanol extract of Kratom can significantly suppress the development of carrageenan-induced rat paw edema and reduce granulomatous tissue formation in a dose-dependent manner.
- No articles (pre-clinical or clinical) that directly investigated and demonstrated these effects were found while two review papers suggested unclear contributions of immune enhancing effects of kratom towards anti-inflammatory effects.
- Based on studies conducted in other plants such as Cat’s claw (Uncaria tomentosa), it was inferred that two compounds which can be found in minute quantities in Kratom may have the potential to contribute towards immunostimulatory effects,
- Kratom leaves:
- Aqueous and ethanol extract of kratom has LD50 range from 2000 to 3000mg/kg in Sprague Dawley rats while methanol extract of kratom showed toxicity between 100 to 1000mg/kg with toxic effects to liver, kidney and lung in male albino Sprague Dawley rats.
- Two case reports showing adverse effects (intrahepatic cholestasis) and side effects (withdrawal symptoms of karom) in humans.
- Other parts of kratom:
- Two case reports showing liver toxicity after ingesting kratom in humans.
- Animal study showed mitragynine is relatively safe at lower sub-chronic doses (1-10mg/kg) but exhibited toxicity at a highest dose (sub-chronic 28 days: 100mg/kg).
- Four case studies which showed three deaths and one suffering from seizure due to high mitragynine concentration in blood or urine in humans.
- Drug-herb interaction:
- There is evidence that kratom can inhibit the activities of human recombinant cytochrome P450 (CYP450).
- There are 11 cases of death due to toxic effects of drugs (i.e. propylhexedrine, quetiapine and O-desmethyltramadol) complicated by kratom or mitragynine use.
Kratom has demonstrated some anti-inflammatory properties but only in preclinical studies. Moreover, none of the anti-inflammatory studies were conducted in infectious disease models while data on immunostimulatory effects are scarce. Future studies to expand and extrapolate these findings specifically in the context of viral or respiratory infections is still needed. Therefore, there is currently no good evidence to support kratom as a miracle cure for COVID-19 or any viral respiratory infections. Based on published toxicity studies, safety concerns should be taken seriously as there were reported deaths due to kratom and mitragynine use. It is important to weigh kratom’s unclear potential benefits against the much reported safety risks, especially when compared to other medicinal plants with a better safety profiles.