**Conflict of interest**

anthocyanins, with particularly high levels in darker purple, blue and black coloured fruits [75]. Similar to cannabis plants, the phytochemical profile of Japanese plum varieties is influenced by horticultural practices, processing and storage conditions [75]. Other commercial plants, such as violet cauliflower and Thai purple basil, gain their unusual purple colouring through modifications to anthocyanin regulatory genes [76, 77]. Therefore, it is possible that plants can be manipulated naturally and artificially (i.e., genetically) to maximise anthocyanin content.

The terpenes linalool, α-pinene and β-caryophyllene, as well as flavonoids and anthocyanins confer pro-cognitive, neuroprotective and anti-inflammatory effects in models of cerebral ischemia and Alzheimer's disease, as well as some anxiolytic effects. Most studies have been conducted in pre-clinical (rodent) models; however, pro-cognitive effects of flavonoids and anthocyanins have been shown in human clinical studies of dementia. Overall, combinations of CBD with other key phytochemicals found in cannabis could confer benefits on brain health through a multi-target synergy (entourage effect); however, further research is required.

This chapter has identified a consensus in the scientific literature that specific phytochemicals (CBD, linalool, α-pinene, β-caryophyllene, flavonoids and anthocyanins) found in cannabis plants are beneficial for cognition and brain health in a number of disease states. These compounds are psychoactive as they alter the brain to effect behaviour, and there is some evidence that they can differentially affect healthy individuals (e.g., CBD has no cognitive benefits and linalool has detrimental effects on cognition in healthy subjects). Therefore, societal consideration of 'medicinal cannabis' as a true medicine is necessary, that is, prescribed for patients who require treatment of a clinically diagnosed illness. Further research is needed to inform optimal prescription for treating specific illnesses, including dose, route of administration, long-term clinical efficacy, safety and side effects. There is some evidence to support the existence of an 'entourage effect'—such synergism could arise from a multitarget approach. The united benefits of specific terpenes and flavonoids could boost the therapeutic potential of CBD to improve cognition in disease states that manifest impairment; we are currently investigating these synergies in my laboratory. An other exciting future area of investigation is the identification of select cannabis phytochemical profiles that will treat specific illnesses with optimal efficacy. Following this, efforts towards standardising horticultural and cannabis plant processing practices to ensure optimal and reproducible medicines can be directed towards a proven goal—a translational interface between medical

I wish to acknowledge the work of Ashleigh L. Osborne, Professor Nadia Solowij and Distinguished Professor Xu-Feng Huang as co-investigators on our project examining the

**4.3. Conclusions on the effects of terpenes and flavonoids on the brain**

**5. Overall conclusion**

92 Recent Advances in Cannabinoid Research

science and horticulture.

**Acknowledgements**

There are no conflicts of interest to declare.
