“The bioavailability of apigenin and its O-glycosides in humans was investigated with apigenin-4′-glucuronide (Ap-4′-GlcUA), apigenin-7-glucuronide and apigenin-7-sulfate being identified as in vivo metabolites. Apigenin per se was poorly absorbed with metabolites equivalent to 0.5% of intake excreted in urine 0–24 h post-intake. Consumption of a parsley drink containing apigenin-7-O-(2″-O-apiosyl)glucoside resulted in the peak plasma concentration (Cmax) of Ap-4′-GlcUA occurring after 4 h, indicative of absorption in the lower gastrointestinal tract (GIT). Urinary excretion of the three metabolites corresponded to 11.2% of intake. Ingestion of dried powdered parsley leaves with yogurt extended the Cmax of Ap-4′-GlcUA to 6 h. Consumption of chamomile tea containing apigenin-7′-O-glucoside resulted in a 2 h Cmax of Ap-4′-GlcUA, in keeping with absorption in the upper GIT. Urinary excretion was equivalent to 34% of intake. Intake of the parsley drink provided information on intra- and inter-individual variations in the level of excretion of the apigenin metabolites.”
That is a rather radical finding. Apigenin per se is not absorbed. Dried parsley and Chamomille are better options. How do this forum interpret this research?
A big thank you for posting the full text. Absorption, distribution, and metabolism of natural products and the substances that they contain are not straight-forward calculations of their contents and a presumed general rates of absorption. There might be great differences in the variability between individuals as well as great intra individual variability.
When I buy ”pure” apigenin powder. Do I know what I get when I buy from different companies? And can I estimate how much of that ”something” is absorbed and reaches circulation? And how much actually enters the cells? When it comes to Apigenin the answere seems to be, probably not. I hope someone can convince me to think otherwise. Because apigenin has shown rather amazing effects on many cell lines and in several organ systems and I wish the ITP could test it. But they need to find the right form as well as make sure its active forms can be found in the blood of the mice.
My personal conclusion from the above posted study is that for now, I go back to dried parsley, and if I want a quickly acting sleep aid I brew a cup of strong chamomile tea in the evening. This is in line with my experience with apigenin in powder form. The powder form did nothing to improve my sleep. But I have only tried one form, and not the capsules from a reputable company like Swanson.
“The current study used HPLC-MS and authentic analytical standards to identify structurally-related apigenin metabolites (SRAMs) in human plasma and urine. The impact of the glycosylation pattern of apigenin on the ADME of the flavone was also investigated in acute absorption studies with healthy male adults (n = 4). The findings from this initial study provided the basis for an investigation with a parsley tea, containing apigenin-7-O -(2″-O -apiosyl)glucoside (2 ), in which urinary excretion of SRAMs in a total of 17 feeds was used to assess intra- and inter-volunteer variations in the bioavailability of the diglycoside.”
This paper digs deep into the absorption issue, and how difficult it is to reach therapeutic levels trough food sources.
" The Utility of Apigenin Taken Orally as a Semi-purified Preparation
Comprehensive in vivo studies looking at the pharmacokinetic properties of purified apigenin given by the oral route have not yet been conducted in humans. In rats, doses of apigenin assessed were 13.5 and 60mg/kg (see Table 1 above). While it is difficult to compare the gastrointestinal physiology of rats to humans, in a 70kg adult person, this is equivalent to apigenin doses of 0.9 and 4.2 g, respectively. Compared with the dosing with dietary parsley mentioned above, this would be approximately a 50–240-fold reduction in bulk intake yet should take plasma concentrations into the bioactive range in humans (by simple extrapolation, to at least 5μmol/L). Measurements in rats at the higher oral dose gave a maximal plasma concentration of 1330ng/ml(Ding et al., 2014). With a molecular mass for apigenin of 270g/mol, this equates to 4.9μmol/L. Although an approximation based upon limited data, both the rat model and extrapolation from human data therefore suggest that doses used and approved in experimentation reach systemic levels into the range to achieve biological effects. Indeed, it should be noted that substantially higher doses of apigenin of up to 300mg/kg have been used in mouse models, with no overt toxicity or effect on body weight up to 68 days of exposure (Ai et al., 2017; Tong et al., 2019). …
…Therefore in principle it should be possible, using oral dosing of apigenin capsules, to reach circulatory concentrations that are able to influence the biology of systemic targets. Circulatory apigenin should be available to act through the extracellular milieu for a substantial time. As indicated above there is a persistence of 6–9h after oral ingestion from human parsley consumption (Meyer et al., 2006) and a T1/2 of 2.1–4.2h in rodents (Teng et al., 2012; Ding et al., 2014). With reasonable dosing several times per day, effective levels could be maintained for long enough a period to exert effects on the cell behaviors described in this review.
The oral dosage form necessary in a therapeutic context therefore needs to be of a reasonably purified form of apigenin itself, since the doses of apigenin that are therapeutically relevant cannot be achieved by oral consumption of whole plant products such as parsley. Parsley leaf itself is available in capsule form as a health supplement, with the typical recommended ingestion amount being 2 capsules for a total dose of 900mg. Using an apigenin content for dried parsley of 45mg/g (Sung et al., 2016), this would equate to a daily dose of approximately 40mg apigenin, less than 1% of what is needed for a meaningful clinical outcome on cancer cell behavior, although it may have other beneficial effects on health. Crude plant products are therefore not adequate in this context."
“Enhancing Oral Bioavailability of Apigenin Using a Bioactive Self-Nanoemulsifying Drug Delivery System (Bio-SNEDDS): In Vitro, In Vivo and Stability Evaluations”
