“The global incidence of respiratory diseases and complications is increasing. Therefore, new methods of treatment, as well as prevention, need to be investigated.
A group of compounds that should be considered for use in respiratory diseases is cannabinoids. There are three groups of cannabinoids – plant-derived phytocannabinoids, synthetic cannabinoids, and endogenous endocannabinoids including the enzymes responsible for their synthesis and degradation.
All cannabinoids exert their biological effects through either type 1 cannabinoid receptors (CB1) and/or type 2 cannabinoid receptors (CB2). In numerous studies (in vitro and in vivo), cannabinoids and inhibitors of endocannabinoid degradation have shown beneficial anti-inflammatory, antioxidant, anti-cancer, and anti-fibrotic properties.
Although in the respiratory system, most of the studies have focused on the positive properties of cannabinoids and inhibitors of endocannabinoid degradation. There are few research reports discussing the negative impact of these compounds. This review summarizes the properties and mechanisms of action of cannabinoids and inhibitors of endocannabinoid degradation in various models of respiratory diseases.
A short description of the effects selected cannabinoids have on the human respiratory system and their possible use in the fight against COVID-19 is also presented. Additionally, a brief summary is provided of cannabinoid receptors properties and their expression in the respiratory system and cells of the immune system.”
https://pubmed.ncbi.nlm.nih.gov/34648805/
“Phytocannabinoids are terpenophenolic compounds produced by specialized parts of the Cannabis sativa plant and are found in high concentrations in marijuana and hashish. In most of models, these compounds have shown positive biological properties. Anti-inflammatory, anti-oxidant, anti-cancer and anti-fibrotic actions are especially emphasized.”
https://www.sciencedirect.com/science/article/pii/S0014299921007160?via%3Dihub
“THC, CBD, and CBN were reported as promising candidates against SARS-CoV2 infection, but the mechanism of action of these three cannabinoids is not understood.
“Given the abundancy of angiotensin converting enzyme 2 (ACE-2) receptors density, beyond the lung, the intestine is considered as an alternative site of infection and replication for severe acute respiratory syndrome by coronavirus type 2 (SARS-CoV-2).
“This study consists of a brief psychological intervention, which uses Self-Regulation Therapy (SRT, procedure based on suggestion and classical conditioning), to improve coping with stress and emotionality by reproducing the positive effects of illegal drugs: cannabis, cocaine, ecstasy.
“Decline in cognitive performance, an aspect of the normal aging process, is influenced by the endocannabinoid system (ECS). Cannabinoid receptor 1 (CB1) signaling diminishes with advancing age in specific brain regions that regulate learning and memory and abolishing CB1 receptor signaling accelerates cognitive aging in mice.
“Cannabis contains a multitude of different compounds. One of them, cannabidiol – a non-psychoactive substance – might counteract negative effects of Δ-9-Tetrahydrocannabinol on hippocampus-dependent memory impairment.
“Cannabidiol (CBD) is a non-intoxicating phytocannabinoid whose purported therapeutic benefits and impression of a high safety profile has promoted its increasing popularity.
“The possible evolutionary trend of COVID-19 in South Africa was investigated by comparing the genome of SARS-CoV-2 isolated from a patient in KwaZulu-Natal, South Africa with those isolated from China, Spain, Italy, and United States, as well as the genomes of Bat SARS CoV, Middle East Respiratory Syndrome Coronavirus (MERS-CoV), Mouse Hepatitis Virus (MHV), and Infectious Bronchitis Virus (IBV). Phylogenetic analysis revealed a strong homology (96%) between the genomes of SARS-CoV-2 isolated from KwaZulu-Natal, South Africa and those isolated from the study countries as well as those isolated from bat SARS CoV, MERS-CoV, MHV and IBV. 
“The Endocannabinoid System (ECS) is primarily responsible for maintaining homeostasis, a balance in internal environment (temperature, mood, and immune system) and energy input and output in living, biological systems.