Cannabis Leaf Extract Showed Anti-Inflammatory and Antidepressant Effects in Mice

Cannabis leaf extract (30 mg/kg) reduced immobility in the forced swimming test and increased sucrose preference in LPS-challenged mice, suggesting antidepressant effects. It also improved oxygen levels and inhibited mast cell degranulation in deep cervical lymph nodes. In brain microglial cells, the extracts suppressed multiple inflammatory markers including IL-1B, IL-6, TNF-A, iNOS, and COX-2.

Combined in vivo (mouse inflammation model using LPS) and in vitro (BV2 microglial cell culture) experiments. Mice received 30 mg/kg cannabis leaf extract one hour before LPS administration. Behavioral tests and inflammatory markers were assessed. The main bioactive components were THCA and B-caryophyllene.

Neuroinflammation is increasingly recognized as a driver of depression. This study suggests cannabis extracts may work through anti-inflammatory mechanisms in the brain, with the combined action of multiple compounds (the "entourage effect") potentially more important than any single cannabinoid.

Most cannabis research focuses on THC and CBD in isolation. This study used whole-plant extracts and attributed efficacy to the combined action of multiple phytochemicals, adding to the debate about whether whole-plant preparations offer advantages over isolated compounds.

Animal study with a single dose tested in vivo. The LPS model of inflammation-induced depression does not fully recapitulate human depression. The relative contributions of individual compounds within the extract cannot be determined from this design.