Neem: An Understudied Panacea

Today, neem is still used as traditional medicine. In an ethnobotanical survey of neem’s medicinal uses in India and Indonesia, neem was found to be used for diabetes, headache, heartburn, appetite stimulation, skin diseases, dental care, gastrointestinal disorders, as an insect repellent, and to treat malaria most commonly.[iv] It is not uncommon to see individuals chewing on neem twigs for overall oral health. These uses mirror the historical uses, suggesting an unbroken chain of medicinal implementation of neem. In Ayurveda, it is considered a cooling herb that would thereby treat the hot conditions of diabetes, headache, heartburn, skin eruptions, gingivitis, and malaria.[v] 

When defeating both insects and demons alike, it is neem oil that is used. Neem oil is cold-pressed from the seed and contains the tetranortriterpenoid Azadirachtin. This unique molecule decreases insect feeding as well as actively disrupts the reproductive cycle of feeding insects. It has been found useful in over 200 species of common pests.[vi]  In humans, this same molecule may be directly cytotoxic to cancer cells. It has been found cytotoxic to glioblastoma cell lines,[vii] cervical cancer cell lines,[viii] and also appears to protect beta-cells from human islet amyloid polypeptide dysfunction.[ix] This is the first research of its kind to begin to elucidate the mechanism that neem uses to prevent and treat diabetes and validating a medical claim made by ancient Ayurvedic scholar-physicians 5,000 years prior. 

The other well-studied phytochemical of neem is nimbin and its derivatives such as nimbolide. Nimbin is a triterpenoid that exerts anti-inflammatory, antihistamine, and anti-pyretic activity.[x] A cooling chemical if there ever was one. Additionally, neem is known to contain high amounts of vitamin C, epicatechins (the anti-inflammatory molecules found in green tea), and quercetin.[xi] 

Sadly, if one enters into the research database Pubmed, they will find that if they search for only human trials of neem, 28 results will emerge. The main theme of these being insect repellent, topical use for skin health, and gingival health. To this end, the studies are largely positive, finding neem efficacious in all these categories. Yet still missing are human trials on many of the other medicinal qualities covered. Meanwhile, if one expands to include in-vitro and in-vivo research, a staggering 1,548 results emerge, all with thought-provoking findings. This suggests that while neem is being studied extensively for its myriad of uses, there seems to be a delay in the crossover to human trials. Given its immense history of use in India, Indonesia, and Africa, almost perfectly dovetailing the uses being explored in non-human research, it seems it is high time that explorations of this ancient marvel be better elucidated in human trials, such as the one trial of neem leaf increasing CD4 cell counts in HIV positive patients.[xii] This continued demonstration of efficacy should only light the way towards the increased utility of this unique and highly sustainable panacea.