August 15, 2024 longcha9

Study on the chemical components with HDAC inhibitory activity in Epimedium sagittatum
In eukaryotic cells, histone deacetylases (HDACs) restore the positive charge of histones by removing acetyl groups from lysine residues in the core histone, thereby tightly binding with negatively charged DNA to form structurally dense chromatin and inhibiting transcription of specific genes. Abnormal activation of HDACs is closely related to diseases such as tumorigenesis and abnormal tissue development. The developed histone deacetylase inhibitors (HDACi) have been applied in clinical practice. For example, SAHA and Romidpesion have become therapeutic drugs for skin and peripheral lymphocytic tumors. HDAC inhibitors have diverse structures, including short chain fatty acids such as butyric acid and trichostatin A, cyclic peptides, as well as flavonoids such as genistein and kaempferol, making them a hot topic in new drug discovery. Epimedium is a traditional Chinese medicine that tonifies the kidneys and bones, with effects such as strengthening muscles and bones, resisting rheumatism, and enhancing liver and kidney function; Pharmacological studies have revealed the effects of Epimedium herb on enhancing sexual function, regulating hormones, modulating immunity, and preventing and treating osteoporosis. Epimedium herb contains more than 140 different types of flavonoids, but there are few research reports on the anti osteoporosis active ingredients of Epimedium based on HDAC inhibition mechanism. This article reports the results of our screening and identification of HDAC inhibitory active ingredients in Epimedium sagittatum under the guidance of activity tracing.

This experiment determined that the solvent site with strong inhibition of HDAC activity by the 70% ethanol extract of Epimedium sagittatum was the ethyl acetate site, which was treated with D101 macroporous adsorption resin. The elution products of 40% and 60% ethanol were the HDAC inhibitory active sites (see Figure 1); Eleven compounds were identified through column chromatography separation and spectral analysis guided by activity. Among them, non isopentene substituted flavonoid glycosides (Compound 1) and flavonoid glycosides (Compounds 2-10) all showed stronger HDAC inhibitory activity than icariin, indicating that these components are the main active ingredients in inhibiting HDAC activity in this plant. Among the 9 flavonoid glycosides isolated, 6 were kaempferol-3-O-glucoside, including compound 5 with high yield (kaempferol-3-O-β – D-glucopyranoside), indicating that kaempferol-3-O-glucoside has relatively strong HDAC inhibitory activity. The compounds with lower activity are 7 and 8. Due to the esterification of one or two hydroxyl groups on the sugar group with coumaric acid, the HDAC inhibitory activity of 7 and 8 is lower than that of isorhamnetin-3-O-glucoside (9 and 10), indicating that the esterification of coumaric acid on the sugar group of kaempferol-3-O-glucoside can weaken the HDAC inhibitory activity (see Table 3). However, since the HDAC inhibitor screening kit provides HDAC extracted from the nucleus of HeLa cells, which is a mixture containing different subtypes of HDAC, further research is needed to determine which one or several HDAC activities (functions) are inhibited by the flavonoids found in Epimedium sagittatum.

As mentioned earlier, the inhibition of HDAC can also be achieved by regulating its expression in cells. Our study using HeLa cells showed (as shown in Figure 2) that kaempferol-3-O-alpha-L-actanopyranoside (3), kaempferol-3-O-beta-D-xylopyranoside (4), and kaempferol-3-O-beta-D-glucopyranoside (5) had no significant effect on the expression of type I HDACs, but could significantly inhibit HDAC6 in type II HDACs (compounds 3 and 4). 5) and HDAC10 (compounds 4 and 5) are newly discovered flavonoid HDAC protein expression inhibitors; Among them, 4 simultaneously inhibit the protein expression of other class II (HDAC4-7) and class IV (HDAC9-11) HDACs, and their effects deserve further investigation.

HDAC plays an important role in cell transcriptional regulation, cell cycle progression, and growth and development activities by deacetylating core histones to suppress the transcription of specific genes. Selective HDACi can act on overexpressed HDACs, allowing suppressed genes to be expressed normally, thus playing a role in the treatment of diseases such as tumors, arthritis, and tissue dysplasia. For example, HDAC1-2 (type I) mediates DNA damage repair and is highly expressed in various cancer tissues such as lung cancer and gastric cancer. During radiation therapy for tumors, the simultaneous use of HDAC1-2 inhibitors can prevent tumor cells from undergoing DNA repair and promote cancer cell apoptosis. The abnormal expression of HDAC8 (type I) and HDAC10 (type II) is a hallmark of the progression and malignancy of neuroblastoma. The HDAC6-8-10 inhibitor TH34 can induce tumor cell apoptosis, mitosis interruption, and cell cycle arrest, leading to tumor cell death; The combination of TH34 and retinoic acid can produce a synergistic effect. Upregulation of HDAC4-6-7 (type II) expression leads to downregulation of key transcription factors Runx2 and Qstelix during osteoblast differentiation, which is unfavorable for osteoblast formation; The upregulation of HDAC6 gene and protein expression can also induce deformation and shortening of primitive cilia in osteoblasts, resulting in a decrease in the number of ciliated cells, thereby inhibiting the ALP function of osteoblasts and effectively preventing osteogenic maturation induced by bone morphogenetic protein (BMP). Inhibiting the expression or function of HDAC6 and HDAC4 will facilitate osteoblast differentiation and bone formation, while protecting bone density.

This study data reveals for the first time that the kaempferol-3-O-glucoside (compounds 3, 4, and 5) in Epimedium sagittatum has clear HDAC inhibitor like effects, and their inhibitory effects on HDAC6 protein expression provide experimental evidence for identifying it as a potential anti osteoporosis and anti-tumor active ingredient with kaempferol-3-O-glucoside structural characteristics in Epimedium herb.

Breathing new life into chemistry.

Qingdao Address: No. 216 Tongchuan Road, Licang District, Qingdao.

Jinan Address:No. 1, North Section Of Gangxing 3rd Road, Jinan Area Of Shandong Pilot Free Trade Zone, China.

Factory Address: Shibu Development Zone, Changyi City, Weifang City.

Contact with us by phone or email.

Email: info@longchangchemical.com

 

Tel & WA: +8613256193735

Fill in the form and we will contact you ASAP!

Please enable JavaScript in your browser to complete this form.
Please fill in your company name and personal name.
We will contact you through the email address you filled in.
If you have additional questions, please fill them in here.
en_USEnglish