Could melatonin have a potential adjuvant role in the treatment of the lasting anosmia associated with COVID-19? A review.

INTRODUCTION: Anosmia, the loss of the sense of smell, is usually associated with rhinopathies and has been reported as a common symptom of COVID-19. There is no specific drug to treat this condition, although some evidence suggests that melatonin could promote the recovery of olfactory sensory neurons. METHODS: We set out to perform a narrative review to synthesize the current evidence in this area in respect of our hypothesis that melatonin may be linked with anosmia and play a part in oxidative stress and the regulation of inflammation. The main electronic databases (MEDLINE/PubMed, Embase, and Cochrane) were searched. RESULTS: The search produced 26 articles related to our hypothesis. Some studies examined issues related to melatonin's effects and its use as adjuvant therapy for COVID-19. Despite some studies suggesting that melatonin may have potential in the treatment of COVID-19, to the best of our knowledge, there have been no trials that have used it to treat anosmia associated with the disease. Few articles identified proposed that melatonin might have an effect on olfactory cells. DISCUSSION: Further experimental and clinical research on the role of circadian melatonin in the olfactory system is warranted. This will provide evidence of the use of melatonin in the management of anosmia. A number of identified studies suggest that the imbalanced release of melatonin by the pineal gland associated with sleep disturbance may play a role in anosmia, although the specific pathway is not yet entirely clear. This may be a base for further research into the potential role of melatonin as adjuvant treatment of anosmia.

Effects of Bryophyllum pinnatum Administration on Wistar Rat Pregnancy: Biochemical and Histological Aspects.

INTRODUCTION: Bryophyllum pinnatum is widely used in folk medicine. It has neuropharmacological, anti-inflammatory, immunomodulatory, antidiabetic, hepatoprotective, and nephroprotective effects, among others. It also acts on uterine contractility. It is prescribed by practitioners of anthroposophic medicine for preterm labor, insomnia, and emotional disorders, and has other potential uses in obstetrics. As all drugs currently used in preterm labor have side effects, new tocolytic agents remain an area of active research. OBJECTIVE: To evaluate the effect of B. pinnatum mother tincture (MT) on albino rats and their offspring throughout pregnancy from a biochemical and histological standpoint. METHODS: Longitudinal, prospective, randomized controlled bioassay. This is the second stage of a trial that investigated 60 animals distributed across six equal groups: controls C1 and C2, which received 1 and 25 times the vehicle dose (30% ethanol), B1 and B2 (1- and 25-fold doses of B. pinnatum MT), and B3 and B4 (which received 50- and 100-fold doses of B. pinnatum concentrate). At this stage, blood chemistry parameters (glucose, alanine aminotransferase [ALT], aspartate aminotransferase [AST], creatinine, and blood urea nitrogen) were measured in dams, as well as histological aspects of dam liver, kidney, placenta, and uterine tissue and fetal liver, kidney, heart, and brain. RESULTS: No differences were found between group B1 (therapeutic dose) and its control C1 in relation to glucose, AST, ALT, and creatinine. Group B2 exhibited lower glucose levels than groups C1, B3, and B4. There was no difference in AST across groups. Groups B3 and B4 exhibited higher ALT levels than groups C1 and B1. Groups B1-B4 exhibited higher urea nitrogen levels than group C1. Creatinine levels were higher in groups B2 and B3 than group C1. On morphological evaluation, fatty infiltration of the liver was observed in the alcoholic vehicle control groups (C1 and C2). CONCLUSIONS: Daily administration of B. pinnatum at therapeutic doses (group B1) to pregnant albino rats appears to be safe, with reduced glucose at dose B2, elevated ALT at doses B3 and B4, and increased urea at doses B1 to B4 and creatinine at B2 and B3, but never exceeding the normal reference range. It was not associated with histological changes in specimens of the maternal or fetal structures of interest.