And this naringin. There is several health benefits to it. I am on 6 medications, blood pressure and blood thinners to name a few. I have been warned be careful with grapefruit juice. Is naringin safe to take. Is there another chemical in grapefruit juice that is the problem. Just wondering, i would like to have the health benefits of grapefruit.
Another area in which the search for definite answers continues, is the quest to find the active constituents of grapefruit juice that are responsible for its actions on CYP enzyme systems and Pgp. The components of grapefruit juice that are responsible for clinical drug interactions have yet to be fully determined but the compounds thought to be responsible for this action include flavonoid glycosides (narirutin, naringin, naringinen, quercetin, kaemferol, hesperidin, neohesperidin, didymin, and poncirin) [
8,
31-
34], furanocoumarins (6',7'-dihydroxybergamottin, bergamottin) and sesquiterpen (nootkatone)[
8,
22,
32,
35,
36].
Flavanoids exist in grapefruit juice in the form of glycosides, with naringin being the most abundant. Upon ingestion, these are converted to aglycones and sugars by the action of intestinal flora. Being polyphenolic and electron rich, these compounds can theoretically inhibit the CYP enzymes. However, studies have at most shown an in vitro effect by these compounds on the these enzymes and have failed to identify any in vivo effect by them [
37,
38], leading to an implication that they are probably not the main active ingredients of grapefruit juice [
1,
39]. Studies have even failed to demonstrate any sort of activity in naringin although its metabolite naringinin was observed to be active in vitro. Yet, because of their huge quantities in grapefruit juice, and the fact that naringin is not present in other citrus juices, flavanoids remain a subject of research.
The main focus at present, however, is on furanocoumarins. This group includes Bergamottin, its derivative 6' 7' dihydroxybergamottin (DHB) and a host of other compounds [
40]. Controversy still exists on the degree of their role in the inhibitory effects of grapefruit juice. Several studies have shown DHB [
23,
35,
40] and to an extent Bergamottin [
23] to be important contributors to the grapefruit juice effect. In one study, the inhibitory potency of DHB and four recently isolated furanocoumarins, when mixed with one another, almost approached that of grapefruit juice. Omission of any of the components resulted in decreased potency, suggesting that all major furanocoumarins contribute to the inhibitory effects of grapefruit juice [
40]. However, others have suggested that DHB and Bergamottin are not the primary substances responsible for inhibition of CYP activity clinically [
41,
42]. For now, this topic also remains a subject of intense research
Kiani J, Imam SZ. Medicinal importance of grapefruit juice and its interaction with various drugs. Nutr J. 2007 Oct 30;6:33. doi: 10.1186/1475-2891-6-33. PMID: 17971226; PMCID: PMC2147024.