-methylene blue (NOT RECCOMENDED 4 human consumption....can cause vasoconstriction, nausea, oxygen deprivation, death) ( reversible MAO-A inhibitor, at higher doses also inhibits MAO-B).
-turmeric (active compound curcumin) ---[only when taken with piperine, a.k.a. black pepper, piperine slows down curcumin metabolism](reversibly inhibits MAO-A and MAO-B) "140 to 560 mg/kg for 14 days, were able to elicit dose-dependent relation of immobility reduction in the tail suspension test and the forced swimming test in mice. The effects of the extracts at the dose of 560 mg/kg were more potent than that of reference antidepressant fluoxetine. The extracts, at the dose of 140 mg/kg or above for 14 days, significantly inhibited the monoamine oxidize A (MAO) activity in mouse whole brain at a dose-dependent manner, however, oral administration of the extract only at a dose of 560 mg/kg produced observable MAO B inhibitory activity in animal brain"
-Geiparvarin, a substance in the Australian Willow, MAO-B inhibitor
-catechin / catechins, found in green Tea, and tons of other fruits/vegetables/random stuff, ..MAO-B inhibitor
-cats Claw (Uncaria tomentosa) contains Catechin, epicatechin, and other compounds, ..MAO-B inhibitor(s)
-harmaline (strong reversible inhibitor of MAO-A, questionable inhibition of MAO-B), found in Syrian Rue, Banisteriopsis Caapi and many other amazonian plants. can cause NAUSEA, anxiety, and hallucinations.
-passion flower (very weak, questionable efficacy, probably due to content of harmaline alkaloids)
-emodin, a substance in rhubarb stalks (not in leaves, the leaves are poisonous) ,... also found in Japanese Knotweed (inhibition of MAO-B, however emodin also increases estrogenic activity)
-coffee (most commonly exibits weak non-selective inhibition, due to harmaline alkaloids. highest levels of these alkaloid are found in ready to drink (instant) coffee)
-wild green oats (a.k.a. oats, but some differences exist) have been shown to have some inhibitory activity upon MAO-B enzymes. this is questionable, only a few studies have been done on it. however, oats have been proven to raise levels of free testosterone in the body, many studies have confirmed oats as having aphrodisiac properties.
-Syrian Rue, also Banisteriopsis Caapi, (contain harmaline alkaloids, very potent MAO-A inhibitor, can cause hallucinations, and vomiting)
-Kaempferol, a substance found in onions, teas, broccoli, strawberries, and tons of other stuff (google it) has been shown to have potent MAO-A inhibition.
-Apigenin, a citrus bioflavonoid, also found in several herbs including chamomile, parsley, thyme, celery, and mugwort, has shown potent MAO-A inhibitory activity. One micromole (uM) of apigenin inhibited 50% of mouse brain MAO.
-Piperine, the principal chemical responsible for spicyness in black pepper, has shown weak MAO-A and MAO-B inhibitory properties. However, piperine should be taken in caution, because it can significantly slow the metabolism of many drugs, causing body levels of the drug to increase greatly.....
-red yeast rice posesses potent MAO-A and MAO-B inhibitory properties.
-quercetin = MAO-A inhibition, weaker MAO-B inhibition.
-Maclura tricuspidata (active ingredient "gancaonin A") = potent MAO-B inhibition, lesser MAO-A inhibition
-red clover, containing Formononetin, strongly inhibited MAO-A and B.
-Sophora flavescens, a chinese plant, posesses strong inhibition of MAO-A and B, this plant also supresses substance P, and has a putative agonist activity at mu and kappa opioid receptors .