Bioavailability, pharmacokinetics, and tissue distribution of the oxypregnane steroidal glycoside P57AS3 (P57) from Hoodia gordonii in mouse model

Natural product P57 induces hypothermia through targeting pyridoxal kinase

Induction of hypothermia during hibernation/torpor enables certain mammals to survive under extreme environmental conditions. However, pharmacological induction of hypothermia in most mammals remains a huge challenge. Here we show that a natural product P57 promptly induces hypothermia and decreases energy expenditure in mice. Mechanistically, P57 inhibits the kinase activity of pyridoxal kinase (PDXK), a key metabolic enzyme of vitamin B6 catalyzing phosphorylation of pyridoxal (PL), resulting in the accumulation of PL in hypothalamus to cause hypothermia. The hypothermia induced by P57 is significantly blunted in the mice with knockout of PDXK in the preoptic area (POA) of hypothalamus. We further found that P57 and PL have consistent effects on gene expression regulation in hypothalamus, and they may activate medial preoptic area (MPA) neurons in POA to induce hypothermia. Taken together, our findings demonstrate that P57 has a potential application in therapeutic hypothermia through regulation of vitamin B6 metabolism and PDXK serves as a previously unknown target of P57 in thermoregulation. In addition, P57 may serve as a chemical probe for exploring the neuron circuitry related to hypothermia state in mice.

Effects of Hoodia Parviflora on satiety, abdominal obesity and weight in a group of overweight subjects: a randomized, blinded, placebo-controlled trial

BACKGROUND

This study aimed to assess the effects of supplementation with Hoodia Parviflora (H. Parviflora) at 9 mg+200 mg of fructo-oligosaccharides on weight loss, body composition, hydration and satiety parameters.

METHODS

A randomized blinded controlled trial was conducted in a sample of 30 overweight and obese patients (5 males and 25 females). Patients were randomly assigned in 2 groups: the intervention group, which received H. Parviflora twice a day for 4 weeks and the control group, which received a placebo.

RESULTS

After a 4-week follow-up period, the study results showed an improvement of Δ=-1.632 kg (Confidence Interval [CI]95% -2.545; -0.719) and a statistically significant decrease in waist circumference (WC) compared with the placebo group -2.080 cm ([CI]95% -4.082; -0.078). The visual analogue scale reported an improvement of satiety sensation after day 5 (P=0.001).

CONCLUSIONS

This study shows for the first time the simultaneous effect of H. Parviflora on weight loss, decreasing satiety, and improving fat mass, in particular Visceral Adipose Tissue (VAT).

Quantitative determination and pharmacokinetic study of fusaricidin A in mice plasma and tissues using ultra-high performance liquid chromatography-tandem mass spectrometry

Fusaricidins are a family of cyclic lipodepsipeptides that convey antifungal and antibacterial activity. Fusaricidin A (FA) is one of the Fusaricidins major compounds and it is showing promising activity against fungi and bacteria. In the present study, a fast and sensitive ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry (UHPLC-MS/MS) method was developed for the analysis of FA in mice plasma, liver, kidney and brain tissues. The instrument was operated in positive electrospray ionization mode. Multiple reaction monitoring (MRM) mode was performed with ion pairs of m/z: 883.5→256.3, 883.5→197.2 and 883.5→72.1 for FA. The method was validated for linearity, repeatability, accuracy, stability, limits of detection (LOD) and limits of quantification (LOQ). The LOD and LOQ were 0.01 and 0.05 ng/mL for plasma and tissues, respectively. The calibration curve (10-200 ng/mL) was linear ( r² = 0.99). Precision and accuracy values were found to be < 10% (within acceptable limit). The pharmacokinetic and tissue distribution characteristics of FA were determined in plasma, liver, kidney and brain of CD1 mice after I.V. administration of a single dose of 15 mg/kg body weight. Highest plasma concentration (C_max) was calculated to be 4169.97 ± 50 ng/mL with a t_max of 0.08 h. The plasma clearance rate of FA was 397.6 ± 203 mL/h with a t_1/2 of 2.2 ± 0.5 h and apparent volume of distribution during the terminal phase (V_z) of 979.2 ± 318 mL. The highest tissue concentration (C_max) was found in the liver (219 ± 14 ng/mg) at a t_max of 0.08 h followed by the kidneys (38.6 ± 16 ng/mg) at t_max of 0.2 h. FA was poorly distributed to the brain with a C_max of 0.45 ± 0.2 ng/mg and a t_max of 0.08 h. The method for quantitative analysis and pharmacokinetic data provided will support the development of various formulation approaches and therapeutic application for future clinical studies.

Molecular matchmaking between the popular weight-loss herb Hoodia gordonii and GPR119, a potential drug target for metabolic disorder

African cactiform Hoodia gordonii (Asclepiadaceae) has been used for thousands of years by Xhomani Bushmen as an anorexant during hunting trips and has been proposed as a new agent for the management of body weight. However, its in vivo targets and molecular mechanisms remain elusive. GPR119, a G protein-coupled receptor highly expressed in pancreatic β cells and intestinal L cells, has been demonstrated to facilitate glucose-stimulated insulin secretion (GSIS) and represents a novel and attractive target for the therapy of metabolic disorders. Here, we disclose that Gordonoside F (a steroid glycoside isolated from H. gordonii), but not the widely known P57, activates specifically GPR119. Successful synthesis of Gordonoside F facilitates further characterization of this compound. Gordonoside F promotes GSIS both in vitro and in vivo and reduces food intake in mice. These effects are mediated by GPR119 because GPR119 knockout prevents the therapeutic effects of Gordonoside F. Interestingly, the appetite-suppressing effect of Hoodia extract was also partially blocked by GPR119 knockout. Our results demonstrate for the first time, to our knowledge, that GPR119 is a direct target and one of the major mechanisms underlying the therapeutic effect of the popular "weight loss" herb H. gordonii. Given the long history of safe application of this herb in weight control, it is foreseeable that the novel scaffold of Gordonoside F provides a promising opportunity to develop new drugs in treating metabolic diseases.

Hoodia gordonii: to eat, or not to eat

ETHNOPHARMACOLOGICAL RELEVANCE

Hoodia gordonii (family Apocynaceae) has become known globally for its claimed effect of appetite suppression. Despite a relatively large body of evidence of the plant׳s chemical make-up, peer-reviewed studies to provide scientific information on physiological effects of Hoodia gordonii are relatively sparse. The role of the pregnane glycoside P57-commonly accepted to be responsible for appetite suppression-has been questioned recently. Furthermore, a variety of physiological side-effects associated with consumption of the plant in extracted form questions its suitability for consumption. Although adverse effects have been described before, the relative abundance of non-peer-reviewed data originating from patent documents and lay publication for advertising, which specifically only focus on beneficial outcomes, skews the view of the risk-benefit-balance. Here we provide a review of peer-reviewed studies on the plant׳s physiological effects. Novel data from an in vivo rodent study further elucidate the benefit-to-risk ratio associated with consumption.

CONCLUSIONS

we conclude that although Hoodia gordonii seems to have a desired effect on appetite and weight loss, this effect may at least in part be a secondary symptom of the serious adverse effects that are associated with consumption of the high doses required to achieve therapeutic clinical effect.

Hoodia gordonii extract targets both adipose and muscle tissue to achieve weight loss in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Hoodia gordonii (Masson) Sweet ex Decne (family Apocynaceae) is consumed globally as a natural appetite suppressant. While this effect-and its subsequent effect of weight loss-has been reported in the scientific literature, no information is available on the specific tissue types affected that accounts for the significant weight loss reported after consumption of the plant. Furthermore, most studies are performed on lean animals, so that the response of overweight or obese individuals to this plant supplement remains largely unknown.

MATERIALS AND METHODS

Twelve lean and twelve obese male Wistar rats were supplemented with different doses of Hoodia gordonii extract (80 or 160 mg/kg body mass twice daily) in a placebo-controlled study, for a period of 14 days.

RESULTS

All supplemented rats exhibited significant weight loss (P<0.001). This could be ascribed to decrease in both adipose cell size and skeletal muscle fibre size.

CONCLUSIONS

We conclude that the weight loss seen after consumption of Hoodia gordonii is due to loss of both adipose and muscle mass.

Sympathomimetic activity of a Hoodia gordonii product: a possible mechanism of cardiovascular side effects

Hoodia gordonii, a popular appetite suppressant, is widely used as an ingredient in many food supplements despite the fact that supporting scientific evidence is scarce. Recently alarming side effects of H. gordonii products (increased blood pressure and elevated pulse rate) have been reported. The aim of our study was to elucidate the underlying mechanism of these symptoms. A H. gordonii-containing product was tested for sympathomimetic activity. Isolated organ experiments on rat uterine rings revealed smooth muscle relaxant effect with a substantial component mediated through β -adrenergic receptors. Chromatographic comparison of the analyzed product and authentic plant material confirmed that the herbal product contained Hoodia spp. extract, and its cardiovascular effects may be linked to the compounds of the plant.

Effects of pregnane glycosides on food intake depend on stimulation of the melanocortin pathway and BDNF in an animal model

Pregnane glycosides appear to modulate food intake by possibly affecting the hypothalamic feeding circuits; however, the mechanisms of the appetite-regulating effect of pregnane glycosides remain obscure. Here, we show that pregnane glycoside-enriched extracts from swamp milkweed Asclepias incarnata at 25-100 mg/kg daily attenuated food intake (up to 47.1 ± 8.5% less than controls) and body weight gain in rats (10% for males and 9% for females, respectively) by activating melanocortin signaling and inhibiting gastric emptying. The major milkweed pregnane glycoside, ikemagenin, exerted its appetite-regulating effect by decreasing levels of agouti-related protein (0.6-fold) but not NPY satiety peptides. Ikemagenin treatment also increased secretion of brain-derived neurotropic factor (BDNF) downstream of melanocortin receptors in the hypothalamus (1.4-fold) and in the C6 rat glioma cell culture in vitro (up to 6-fold). These results support the multimodal effects of pregnane glycosides on feeding regulation, which depends on the activity of the melanocortin signaling pathway and BDNF.

Effects of 15-d repeated consumption of Hoodia gordonii purified extract on safety, ad libitum energy intake, and body weight in healthy, overweight women: a randomized controlled trial

BACKGROUND

Extracts from Hoodia gordonii have been shown to decrease food intakes and body weights in animals and were proposed as a food supplement or ingredient for weight management.

OBJECTIVE

We assessed the safety and efficacy of a 15-d repeated consumption of H. gordonii purified extract (HgPE) relative to a placebo in humans.

DESIGN

Healthy, overweight women, who were stratified by percentage body fat, received either HgPE (n = 25) or a placebo (n = 24) for 15 d. Subjects were resident in a clinic for a 4-d run-in period and a 15-d treatment period in which they received 2 servings/d of 1110 mg HgPE or a placebo formulated in a yogurt drink 1 h before breakfast and dinner. Subjects were otherwise allowed to eat ad libitum from standardized menus.

RESULTS

There were no serious adverse events, but HgPE was less well tolerated than was the placebo because of episodes of nausea, emesis, and disturbances of skin sensation. Blood pressure, pulse, heart rate, bilirubin, and alkaline phosphatase showed significant (P < 0.05) increases in the HgPE group. Mean effects on ad libitum energy intakes and body weights did not differ significantly between the HgPE- and placebo-treatment groups (P > 0.05).

CONCLUSIONS

In comparison with a matched placebo, the consumption of HgPE for 15 d appeared to be associated with significant adverse changes in some vital signs and laboratory parameters. HgPE was less well tolerated than was the placebo and did not show any significant effects on energy intakes or body weights relative to the placebo. This trial was registered at clinicaltrials.gov as NCT01306422.

In vitro transport of the steroidal glycoside P57 from Hoodia gordonii across excised porcine intestinal and buccal tissue

Hoodia gordonii was traditionally used by the Khoisan people as a thirst and appetite suppressant and is currently commercially available as a popular weight-loss supplement. The perceived active ingredient isolated from this plant is a steroidal glycoside named P57. This study aimed at investigating the in vitro transport of P57 across excised porcine intestinal and buccal mucosa in a Sweetana-Grass diffusion apparatus. For both the intestinal and buccal experiments, the transport of pure P57 was compared to that obtained from a crude plant extract. Bi-directional transport experiments were conducted across the intestinal tissue in two different media namely Krebs-Ringer bicarbonate buffer and simulated intestinal fluid. Apical-to-basolateral transport experiments were conducted across the buccal tissue in two different media namely Krebs-Ringer bicarbonate buffer and artificial saliva. Apparent permeability coefficient (P(app)) and flux values were calculated and analysed by means of a one-way repeated analysis of variance (ANOVA) to determine if differences were significant (p≤0.05). The transport of pure P57 across intestinal tissue was significantly higher in the secretory direction than in the absorptive direction indicating efflux by membrane transporters. Much higher intestinal transport was obtained for P57 in both directions when applied in the form of a crude extract, possibly due to inhibition of efflux as indicated by lower secretory transport compared to absorptive transport. For the buccal tissue, no transport was obtained for the pure P57, while relatively high transport was obtained when applied in the form of a crude extract. Furthermore, the intestinal transport of P57 was significantly decreased when the crude extract was prepared in simulated intestinal fluid compared to when it was prepared in buffer. On the other hand, buccal transport was higher in artificial saliva than in buffer. It is therefore evident that the transport of P57 across mucosal tissues is significantly affected on exposure to conditions simulating the in vivo situation.