Arbutin abrogates testicular ischemia/reperfusion injury in rats through repression of inflammation and ER stress

Preparation, characterization and analysis of anthocyanin arbutin co-amorphous complexes and evaluation of the inhibition of tyrosinase

Natural phenolic compounds, such as anthocyanins and arbutin, have demonstrated significant potential as tyrosinase (TYR) inhibitors. However, the application of anthocyanins in biological systems is hindered by their instability under alkaline conditions, elevated temperatures, and light exposure. In contrast, arbutin exhibits superior stability while also functioning as a TYR inhibitor. To overcome these limitations, this study developed an Anthocyanin-α-Arbutin Co-amorphous (AAC) system aimed at enhancing both the stability of anthocyanins and their TYR inhibitory properties. Kinetic studies revealed that anthocyanins, arbutin, and AAC act as reversible mixed-type TYR inhibitors, with competitive inhibition as the predominant mechanism. Each compound exhibited distinct inhibition sites. Fluorescence analysis demonstrated that anthocyanins induce a fluorescence burst in TYR, likely attributed to Tyr residues, whereas α-arbutin and AAC enhance the fluorescence intensity of TYR. Moreover, α-arbutin and AAC were found to decrease the microenvironmental hydrophobicity surrounding tyrosine (Tyr) residues while increasing it around tryptophan (Trp) residues, suggesting potential conformational changes in tyrosinase. Molecular docking analysis indicated that hydrogen bonding and π-π stacking interactions occurred between anthocyanins and arbutin in the AAC system. Specifically, anthocyanins primarily interacted with TYR through π-π and π-alkyl interactions, while α-arbutin predominantly bound to TYR via hydrogen bonding. Consistent with the interaction study, α-arbutin was found to associate with tyrosinase mainly through hydrogen bonding and van der Waals forces. These findings provide novel insights into the interactions between anthocyanins and α-arbutin in the context of food science and lay a foundation for the development of innovative TYR inhibitors.

Melatonin as a natural anti-inflammatory and anti-oxidant therapy in the testis: a focus on infertility and aging†

Melatonin is a pineal hormone that regulates testicular activity (i.e., steroidogenesis and spermatogenesis) through two complementary mechanisms, indirect effects exerted via the hypothalamic-adenohypophyseal axis and direct actions that take place on the different cell populations of the male gonad. The effects of increased age on the testis and the general mechanisms involved in testicular pathology leading to infertility are still only poorly understood. However, there is growing evidence that link testicular aging and idiopathic male infertility to local inflammatory and oxidative stress events. Because literature data strongly indicate that melatonin exhibits anti-inflammatory and anti-oxidant properties, this review focuses on the potential benefits exerted by this indoleamine at testicular level in male reproductive fertility and aging. Taking into account that the effects of melatonin supplementation on testicular function are currently being investigated, the overview covers not only promising prospects but also many questions concerning the future therapeutic value of this indoleamine as an anti-aging drug as well as in the management of cases of male infertility for which there are no medical treatments currently available.

Protective effects of arbutin against doxorubicin-induced cardiac damage

BACKGROUND

Doxorubicin is an effective antineoplastic agent but has limited clinical application because of its cumulative toxicities, including cardiotoxicity. Cardiotoxicity causes lipid peroxidation, genetic impairment, oxidative stress, inhibition of autophagy, and disruption of calcium homeostasis. Doxorubicin-induced cardiotoxicity is frequently tried to be mitigated by phytochemicals, which are derived from plants and possess antioxidant, anti-inflammatory, and anti-apoptotic properties. Arbutin, a natural antioxidant found in the leaves of the bearberry plant, has numerous pharmacological benefits, including antioxidant, anti-bacterial, anti-hyperglycemic, anti-inflammatory, and anti-tumor activity.

METHODS AND RESULTS

The study involved male Wistar rats divided into three groups: a control group, a group treated with doxorubicin (20 mg/kg) to induce cardiac toxicity, a group treated with arbutin (100 mg/kg) daily for two weeks before doxorubicin administration. After treatment, plasma and heart tissue samples were collected for analysis. The samples were evaluated for oxidative stress parameters, including superoxide dismutase, malondialdehyde, and catalase, as well as for cardiac biomarkers, including CK, CK-MB, and LDH. The heart tissues were also analyzed using molecular (TNF-α, IL-1β and Caspase 3), histopathological and immunohistochemical methods (8-OHDG, 4 Hydroxynonenal, and dityrosine). The results showed that arbutin treatment was protective against doxorubicin-induced oxidative damage by increasing SOD and CAT activity and decreasing MDA level. Arbutin treatment was similarly able to reverse the inflammatory response caused by doxorubicin by reducing TNF-α and IL-1β levels and also reverse the apoptosis by decreasing caspase-3 levels. It was able to prevent doxorubicin-induced cardiac damage by reducing cardiac biomarkers CK, CK-MB and LDH levels. In addition to all these results, histopathological analyzes also show that arbutin may be beneficial against the damage caused by doxorubicin on heart tissue.

CONCLUSION

The study suggests that arbutin has the potential to be used to mitigate doxorubicin-induced cardiotoxicity in cancer patients.

Alpha-pinene neutralizes cisplatin-induced reproductive toxicity in male rats through activation of Nrf2 pathway

PURPOSE

Testicular toxicity is one of the most important side effects of cisplatin (CP) therapy. Alpha-pinene (AP) is a naturally occurring monoterpene with antioxidant character in plants. Here, we aimed to evaluate the therapeutic activity of AP against CP-induced testicular toxicity by including the nuclear factor erythroid 2-associated factor 2 (Nrf2) pathway in rats.

METHODS

Thirty male rats were divided into 5 groups: control, CP, CP + AP (5 and 10 mg/kg) and only AP (10 mg/kg). CP was administered intraperitoneally at a dose of 5 mg/kg on the first day, followed by three consecutive injections of AP. Serum reproductive hormone levels were evaluated using ELISA kits. Oxidative stress (OS), inflammation, endoplasmic reticulum stress (ERS) and apoptosis markers in testicular tissue were also determined colorimetrically. In addition, how CP affects Nrf2 pathway and the effect of AP on this situation were also addressed.

RESULTS

Treatment with CP significantly increased OS, inflammation, ERS and apoptosis in testicular tissue. Administrations of AP resulted in an amelioration of these altered parameters. The mechanism of therapeutic effect of AP appeared to involve induction of Nrf2. Furthermore, these results were also confirmed by histological data.

CONCLUSION

Results suggest that AP can exhibit therapeutic effects against CP-induced testicular toxicity. It can be concluded that AP may be a potential molecule to abolish reproductive toxicity after chemotherapy.

LncRNA Peg13 Alleviates Myocardial Infarction/Reperfusion Injury through Regulating MiR-34a/Sirt1-Mediated Endoplasmic Reticulum Stress

Myocardial infarction/reperfusion (I/R) injury significantly impacts the health of older individuals. We confirmed that the level of lncRNA Peg13 was downregulated in I/R injury. However, the detailed function of Peg13 in myocardial I/R injury has not yet been explored.To detect the function of Peg13, in vivo model of I/R injury was constructed. RT-qPCR was employed to investigate RNA levels, and Western blotting was performed to assess levels of endoplasmic reticulum stress and apoptosis-associated proteins. EdU staining was confirmed to assess the cell proliferation.I/R therapy dramatically produced myocardial injury, increased the infarct area, and decreased the amount of Peg13 in myocardial tissues of mice. In addition, hypoxia/reoxygenation (H/R) notably induced the apoptosis and promoted the endoplasmic reticulum (ER) stress of HL-1 cells, while overexpression of Peg13 reversed these phenomena. Additionally, Peg13 may increase the level of Sirt1 through binding to miR-34a. Upregulation of Peg13 reversed H/R-induced ER stress via regulation of miR-34a/Sirt1 axis.LncRNA Peg13 reduces ER stress in myocardial infarction/reperfusion injury through mediation of miR-34a/Sirt1 axis. Hence, our research might shed new lights on developing new strategies for the treatment of myocardial I/R injury.

Evaluation of the therapeutic effects of arbutin on cisplatin-induced ovarian toxicity in rats through endoplasmic reticulum stress and Nrf2 pathway

Arbutin (ARB) is a glycosylated hydroquinone with potent antioxidant effects. Although cisplatin (CP) is widely used in chemotherapy, its toxicity in healthy tissues, including ovotoxicity, is an insurmountable problem. This study aimed to evaluate the therapeutic effect of ARB against CP-related ovototoxicity by including nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in rats for the first time. Rats treated one dose of CP (5 mg/kg) on the first day, followed by ARB (5 and 10 mg/kg) for three days. Serum reproductive hormone levels were determined using ELISA kits. Oxidative stress (OS), inflammation, endoplasmic reticulum stress (ERS) and apoptosis markers in ovarian tissue were also determined colorimetrically. In addition, how CP affects Nrf2 pathway and the effect of ARB on this situation were also addressed. ARB treatment reduced the levels of markers of OS, inflammation, ERS and apoptosis in ovarian tissue of CP-stimulated animals. ARB regenerated the depleted antioxidant system by triggering Nrf2 pathway in the ovarian tissues of animals stimulated by CP. Histological findings also supported the therapeutic efficacy of ARB. The results indicate that ARB may have therapeutic effects against CP-induced reproductive toxicity with its Nrf2 activator potential. ARB should be tested in more extensive studies as a new generation chemopreventive candidate molecule.