Effects of the Aqueous Extract of Eremomastax speciosa (Acanthaceae) on Sexual Behavior in Normal Male Rats

Sea cucumber peptides positively regulate sexual hormones in male mice with acute exhaustive swimming: possibly through the Ca2+/PKA signaling pathway

Sea cucumber peptides (SCPs) have been proven to have many active functions; however, their impact on testosterone synthesis and the corresponding mechanism are not yet clear. This study attempts to explore the effects of SCPs on sex hormone regulation in acute exhaustive swimming (AES) male mice and the possible mechanisms. In the present study, SCP intervention significantly prolonged exhaustive swimming time and reduced exercise metabolite accumulation. The reproductive ability-related parameters including penile index, mating ability, testicular morphology, and sperm storage were dramatically improved by SCP intervention. Notably, SCPs markedly reversed the AES-induced decrease in serum testosterone (T), estradiol (E2), and follicle-stimulating hormone (FSH) levels. Moreover, treatment with a high dose of SCP (0.6 mg per g bw) significantly enhanced the expression of testosterone synthesis-related proteins in testis, meanwhile markedly increasing the gene expression of StAR, Hsd17b3, Hsd17b2, Ldlr, and Cyp19a1. Serum metabolomics results indicated that SCP intervention notably upregulated the expression of 1-stearoyl-2-arachidonoyl-sn-glycerol but downregulated the concentrations of succinate and DL-lactate. Furthermore, serum metabolomics combined with testicular transcriptome, western blot, and correlation analyses demonstrated that SCPs may regulate testosterone synthesis via the Ca2+/PKA signaling pathway. This study indicated that the SCP could be a potential dietary supplement to improve the symptoms of decreased sex hormones related to exercise fatigue.

Effect of Peganum harmala Total Alkaloid Extract on Sexual Behavior and Sperm Parameters in Male Mice

The study was designed to evaluate the effects of the total alkaloid extract of Algerian Peganum harmala seeds on sexual behavior and male reproductive function. After two weeks of acclimatization, the male mice were randomly divided into four groups (seven mice in each group). For 35 days, the extract was administered orally at dose levels of 6.25, 12.5, and 25 mg/kg body weight per day to the respective groups of male mice (n = 7) and normal saline daily to the control group. On day 28, sexual behavior parameters were recorded. At the end of the trial, reproductive organ weights, sperm quality, seminal fructose, and testosterone hormone levels were evaluated. The three treated groups were compared with the control using statistical variance analysis (one-way ANOVA, p < 0.05), followed by Tukey's test. The results of the groups treated with 12.5 and 6.25 mg/kg of P. harmala alkaloid revealed the MF and IF parameters to be the lowest compared to the control group (p < 0.05). However, the male mice treated with 25 mg/kg recorded the highest values. A low significant value of ML was observed in the group treated with 25 mg/kg of the total alkaloid extract of P. harmala compared to the control group (p < 0.01), while a rise was observed in the concentration group treated with 6.25 mg/kg. Regarding IL, the male mice treated with different concentrations of the total alkaloid extract of P. harmala recorded a higher time than the control group. Moreover, an increase in the gonadosomatic index was noticed in all groups compared to the control group. However, there was a significant (p < 0.01) decrease in the sperm counts of the groups treated with 12.5 mg/kg and 6.25 mg/kg. However, there was no significant difference in the motility, membrane integrity, and total antioxidant capacity of sperm cells compared to the control. The extract treatment also brought about a non-significant increase in fructose content of the seminal vesicle and serum testosterone level. The findings of this study demonstrate that the extract acts in a dose-dependent manner, and it has varying effects on the reproductive parameters of male mice.

Almond-supplemented diet improves sexual functions beyond Phosphodiesterase-5 inhibition in diabetic male rats

Hyperglycemia, an important feature of diabetes, can cause oxidative stress, which is associated with varieties of diabetic complications including erectile dysfunction. Therefore, this study sought to investigate the effect of almond-supplemented diet on some biochemical indices relevant to erection in diabetic male rats. Forty-two male rats were divided into two groups: A (n = 6) and B (n = 36). Diabetes was induced in Group B via injection of a single dose of STZ (50 mg/kg) intraperitoneally and confirmed 72 h after induction. Diabetic rats (blood glucose ≥250 mg/dL) were subsequently divided into six groups (n = 6). Fourteen days after confirmation of diabetes, rats were fed with diets containing almond drupe and seeds (10 and 20% inclusion) for fourteen days. The effects of the diets on blood glucose, sexual behavior, sexual hormones, phosphodiesterase-5 activity, nitric oxide, H₂S, and AGEs levels were evaluated. Significant increase in blood glucose level, phosphodiesterase-5 activity, and glycated hemoglobin was observed in diabetic rats. Furthermore, diabetes caused a significant decrease in nitric oxide, H₂S, sexual hormones (testosterone, follicle-stimulating hormone and luteinizing hormone) levels, and sexual behavioral indices. However, treatment with diets supplemented with almond drupe and seeds significantly reversed these effects in diabetic rats. Findings in this study revealed that almond-supplemented diets enhance some important biomarkers relevant to erection in diabetic rats. Thus, dietary inclusion of almond (drupe and seeds) could serve as a cheap and readily available nutraceutical in the management of erectile dysfunction associated with diabetes.

Alkaloid extracts from Bitter leaf (Vernonia amygdalina) and Black nightshade (Solanum nigrum) inhibit phosphodiesterase-5, arginase activities and oxidative stress in rats penile tissue

The erectogenic potential of alkaloids extracted from Bitter leaf (Vernonia amygdalina) and Black nightshade (Solanum nigrum) was investigated in this study. Fresh leaves obtained from Bitter leaf and Black night shade were air-dried, pulverized, and extracted for alkaloids. The inhibitory potential of the alkaloid extracts on arginase and phosphodiesterase-5 (PDE-5) activities in rats penile tissue was determined in vitro. The antioxidant properties were also evaluated and the constituent alkaloids quantified using GC-MS. The alkaloid extracts inhibited arginase (0-30.51 μg/ml) and PDE-5 (0-133.69 μg/ml) activities in a concentration-dependent pattern. Similarly, the alkaloid extracts inhibited Fe²⁺ -induced lipid peroxidation in rats penile tissues, scavenged DPPH, OH, and NO radicals as a function of concentration. GC-MS characterization revealed over 20 alkaloid compounds. The inhibition of PDE-5-, arginase-, pro-oxidant-induced lipid peroxidative-, and free radicals-scavenging activities by the alkaloids is suggestive of putative mechanisms underlying their therapeutic use for managing erectile dysfunction in folklore medicine. PRACTICAL APPLICATIONS: Alkaloids extracted from Black nightshade (Solanum nigrum) and Bitter leaf (Vernonia amygdalina) were characterized and investigated by standard procedures for inhibitory action against key erectile dysfunction-linked enzymes and antioxidant activity. The alkaloids inhibited erectile dysfunction-linked enzymes (arginase and PDE-5) and showed considerable antioxidant activity in a concentration-dependent manner. In view of this, we suggest the application of these results in the development of erectile dysfunction drugs in the pharmaceutical industry, with probable minimal or no adverse effect.