Enzymatic preparation of Crassostrea oyster peptides and their promoting effect on male hormone production.

ETHNOPHARMACOLOGICAL RELEVANCE: Crassostrea gigas Thunberg and other oysters have been traditionally used in China as folk remedies to invigorate the kidney and as natural aphrodisiacs to combat male impotence. AIM OF THE STUDY: Erectile dysfunction (ED) has become a major health problem for the global ageing population. The aim of this study is therefore to evaluate the effect of peptide-rich preparations from C. gigas oysters on ED and related conditions as increasing evidence suggests that peptides are important bioactive components of marine remedies and seafood. MATERIALS AND METHODS: Crassostrea oyster peptide (COP) preparations COP1, COP2 and COP3 were obtained from C. gigas oysters by trypsin, papain or sequential trypsin-papain digestion, respectively. The contents of testosterone, cyclic adenosine monophosphate (cAMP) and nitric oxide (NO) and the activity of nitric oxide synthase (NOS) in mice and/or cells were measured by enzyme-linked immunosorbent assays. Real-time PCR was used to assess the expression of genes associated with sex hormone secretion pathways. The model animal Caenorhabditis elegans was also used to analyze the gene expression of a conserved steroidogenic enzyme. In silico analysis of constituent peptides was performed using bioinformatic tools based on public databases. RESULTS: The peptide-rich preparation COP3, in which >95% peptides were <3000 Da, was found to increase the contents of male mouse serum testosterone and cAMP, both of which are known to play important roles in erectile function, and to increase the activity of mouse penile NOS, which is closely associated with ED. Further investigation using mouse Leydig-derived TM3 cells demonstrates that COP3 was able to stimulate the production of testosterone as well as NO, a pivotal mediator of penile erection. Real-time PCR analysis reveals that COP3 up-regulated the expression of Areg and Acvr2b, the genes known to promote sex hormone secretion, but not Fst, a gene involved in suppressing follicle-stimulating hormone release. Furthermore, COP3 was also shown to up-regulate the expression of let-767, a well-conserved C. elegans gene encoding a protein homologous to human 17-ß-hydroxysteroid dehydrogenases. Preliminary bioinformatic analysis using the peptide sequences in COP3 cryptome identified 19 prospective motifs, each of which occurred in more than 10 peptides. CONCLUSIONS: In this paper, Crassostrea oyster peptides were prepared by enzymatic hydrolysis and were found for the first time to increase ED-associated biochemical as well as molecular biology parameters. These results may help to explain the ethnopharmacological use of oysters and provide an important insight into the potentials of oyster peptides in overcoming ED-related health issues.

[Protective effect of Dendrobium candidum on isoproterenol induced cardiac hypertrophy in rats].

To study the effect and mechanism of Dendrobium candidum on isoproterenol-induced myocardial hypertrophy in rats, 60 healthy SD rats(30 males and 30 females) were randomly divided into 5 groups(12 in each group): normal group, model group, three D. candidum preventive administration groups(0.09, 0.18, 1.1 g·kg⁻¹). Except for the normal group, rats of other groups were injected back subcutaneously with ISO(5 mg·kg⁻¹) for 10 consecutive days. At the same time, preventive administration groups began to give different doses of the sample for 30 days and model group began to give normal saline. Left ventricular systolic pressure(LVSP) was measured in each group by common carotid artery cannulation, and the left ventricle(LW)/tibia length, heart weight index(HWI) and myocardial hydroxyproline(Hydro) content were calculated. Myocardial tissue HE staining and Masson staining were used to observe the myocardial structure and the degree of myocardial fibrosis respectively. Atrial natriuretic peptide(ANP), brain natriuretic peptide(BNP), and cardiac troponin I(cTN-I) concentration were measured by enzyme-linked immunosorbent assay(ELISA). The results showed that as compared with the normal group, the levels of ANP, BNP and cTN-I in plasma were significantly increased in ISO-induced hypertrophic rats; as compared with the model group, D. candidumcan inhibit ISO-induced ventricular pressure and ventricular hypertrophy, reduce myocardial collagen synthesis, improve myocardial fibrosis and ventricular remodeling, and significantly down-regulate ANP, BNP and cTN-I levels in plasma. This study shows that D. candidum has a protective effect on isoproterenol-induced cardiac hypertrophy.

[Comparing the dissolution of Rb1 from the micropowder and common powder of Radix Panacis Quinquefolii].

OBJECTIVE: To compare the dissolution of Rb1 from the micropowder and common powder of Radix Panacis Quinquefolii in vitro. METHODS: The contents of Ginsenoside Rb1 in micropowder (99% over 0-30 microm) and common powder (180 microm) with and without the barrier of dialytic membrane were determined at different time by HPLC. RESULTS: The speed and degree of dissolution of Ginsenoside Rb1 in micropowder were better than those in common powder (15-45 min, P < 0.05; 45-60 min, P < 0.01). CONCLUSION: The dissolution of effective components in Radix Panacis Quinquefolii can be improved by SFCT.