Attenuation of Tumor Development in Mammary Carcinoma Rats by Theacrine, an Antagonist of Adenosine 2A Receptor

2023

Self Cite

Strictinin is a relatively tiny ellagitannin, which is found in many plants as a minor constituent. Catechins are known as the major constituents in the young leaves of most tea plants, while strictinin was found as a major constituent in the Pu’er tea plant. In some Pu’er tea varieties, strictinin was identified as the most abundant phenolic compound rather than catechins. In the past decade, strictinin was demonstrated to possess several functional activities, including antiviral, antibacterial, anti-obesity, laxative, anticaries, anti-allergic, antipsoriatic, antihyperuricemia, antidiabetic, and anticancer effects. These functional activities were in accordance with the therapeutic effects empirically perceived for Pu’er tea. Evidently, strictinin is the key ingredient in Pu’er tea that acts as a herbal medicine. In functionally-based applications, an instant powder of Pu’er tea infusion was formulated as an active raw material to be supplemented in food, cosmetics, and beverages; a new type of tea named Bitter Citrus Tzen Tea was developed by combining three teas empirically consumed to expel the cold, and new edible oral care products were designed for caries prevention by supplementation with Pu’er tea extract. More functional activities and practical applications of strictinin are scientifically anticipated in follow-up research.

Section: Functional Activities Of Strictinin 21 Antiviral Activitymentioning

confidence: 99%

Strictinin: A Key Ingredient of Tea

2023

Self Cite

“…Recently, theacrine and strictinin were identified as two major compounds responsible for the anti-influenza activity of Yunnan Kucha tea [ 18 ]. Theacrine is structurally similar to caffeine, but much more bitter than caffeine in taste, and has been demonstrated to possess several biological activities, including a sedative effect on sleep improvement, ergogenic effect on sports performance, anti-inflammation, anti-depression, and anti-breast cancer [ 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. Strictinin is a hydrolyzable ellagitannin, generally detected as a minor constituent in most tea varieties but abundantly present in Pu’er tea, and has been demonstrated to possess antioxidant, antiviral, antimicrobial, anti-obesity, and anti-psoriatic activities [ 26 , 27 , 28 , 29 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

Strictinin, a Major Ingredient in Yunnan Kucha Tea Possessing Inhibitory Activity on the Infection of Mouse Hepatitis Virus to Mouse L Cells

Hsu

2023

Self Cite

Theacrine and strictinin of Yunnan Kucha tea prepared from a mutant variety of wild Pu’er tea plants were two major ingredients responsible for the anti-influenza activity. As the COVID-19 outbreak is still lurking, developing safe and cost-effective therapeutics is an urgent need. This study aimed to evaluate the effects of these tea compounds on the infection of mouse hepatitis virus (MHV), a β-coronavirus serving as a surrogate for SARS-CoV. Treatment with strictinin (100 μM), but not theacrine, completely eliminated MHV infection, as indicated by a pronounced reduction in plaque formation, nucleocapsid protein expression, and progeny production of MHV. Subsequently, a time-of-drug addition protocol, including pre-, co-, or post-treatment, was exploited to further evaluate the possible mechanism of antiviral activity mediated by strictinin, and remdesivir, a potential drug for the treatment of SARS-CoV-2, was used as a positive control against MHV infection. The results showed that all three treatments of remdesivir (20 μM) completely blocked MHV infection. In contrast, no significant effect on MHV infection was observed when cells were pre-treated with strictinin (100 μM) prior to infection, while significant inhibition of MHV infection was observed when strictinin was introduced upon viral adsorption (co-treatment) and after viral entry (post-treatment). Of note, as compared with the co-treatment group, the inhibitory effect of strictinin was more striking in the post-treatment group. These results indicate that strictinin suppresses MHV infection by multiple mechanisms; it possibly interferes with viral entry and also critical step(s) of viral infection. Evidently, strictinin significantly inhibited MHV infection and might be a suitable ingredient for protection against coronavirus infection.

“…Oolong tea is a semi-fermented tea, in comparison with fully fermented black tea and non-fermented green tea [ 2 ]. The major constituents, catechins and other minor compounds in tea, have been shown to exhibit several biological functions, such as anti-cancer, anti-obesity, anti-oxidant, and anti-viral activities [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. Eight catechins are commonly found in tea, including (−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-epicatechin gallate (ECG), (−)-epigallocatechin gallate (EGCG), (−)-gallocatechin gallate (GCG), (−)-gallocatechin (GC),(−)-catechin gallate (CG) and (+)-catechin (C) [ 10 ].…”

Section: Introductionmentioning

confidence: 99%

Exploring The Relative Astringency of Tea Catechins and Distinct Astringent Sensation of Catechins and Flavonol Glycosides via an In Vitro Assay Composed of Artificial Oil Bodies

Liu

2022

Self Cite

Artificial oil bodies covered by a recombinant surface protein, caleosin fused with histatin 3 (a major human salivary peptide), were employed to explore the relative astringency of eight tea catechins. The results showed that gallate-type catechins were more astringent than non-gallate-type catechins, with an astringency order of epicatechin gallate > epigallocatechin gallate > gallocatechin gallate > catechin gallate > epigallocatechin > epicatechin > gallocatechin > catechin. As expected, the extension of brewing time led to an increase in catechin content in the tea infusion, thus elevating tea astringency. Detailed analysis showed that the enhanced proportion of gallate-type catechins was significantly higher than that of non-gallate-type catechins, indicating that tea astringency was elevated exponentially, rather than proportionally, when brewing time was extended. Rough surfaces were observed on artificial oil bodies when they were complexed with epigallocatechin gallate (a catechin), while a smooth surface was observed on those complexed with rutin (a flavonol glycoside) under an atomic force microscope and a scanning electron microscope. The results indicate that catechins and flavonol glycosides induce the sensation of rough (puckering) and smooth (velvety) astringency in tea, respectively.