Do Certain Flavonoid IMPS Have a Vital Function?

Flavonoids are a vast group of metabolites that are essential for vascular plant physiology and, thus, occur ubiquitously in plant-based/-derived foods. The solitary designation of thousands of known flavonoids hides the fact that their metabolomes are structurally highly diverse, consist of disparate subgroups, yet undergo a certain degree of metabolic interconversion. Unsurprisingly, flavonoids have been an important theme in nutrition research. Already in the 1930s, it was discovered that the ability of synthetic Vitamin C to treat scurvy was inferior to that of plant extracts containing Vitamin C. Subsequent experimental evidence led to the proposal of Vitamin P (permeability) as an essential phytochemical nutrient. However, attempts to isolate and characterize Vitamin P gave confusing and sometimes irreproducible results, which today can be interpreted as rooted in the unrecognized (residual) complexity of the intervention materials. Over the years, primarily flavonoids (and some coumarins) were known as having Vitamin P-like activity. More recently, in a NAPRALERT meta-analysis, essentially all of these Vitamin P candidates were identified as IMPs (Invalid/Improbable/Interfering Metabolic Panaceas). While the historic inability to define a single compound and specific mode of action led to general skepticism about the Vitamin P proposition for “bioflavonoids,” the more logical conclusion is that several abundant and metabolically labile plant constituents fill this essential role in human nutrition at the interface of vitamins, cofactors, and micronutrients. Reviewing 100+ years of the multilingual Vitamin P and C literature provides the rationales for this conclusion and new perspectives for future research.

Growth performance of heat stressed rabbits fed diets supplemented with synthetic and organic antioxidants

The aimof the studywas to evaluate the growth performance of heat stressed rabbits fed diets supplemented with synthetic and organic antioxidants. The antioxidants used were bicarbonate buffers, vitamin C and baobab fruit pulp meal (BFPM). A total of thirty (30) growing rabbits were used. The rabbits were allotted into the treatment groups with six (6) rabbits per treatment in a completely randomized design. Rabbits in the first group (T ) were the control, animals in treatment 2 and treatment 3 (T ) and (T ) were fed similar diets as in the control but with potassium bicarbonate (KHCO ) and sodium bicarbonate (NaHCO ) buffer solutions, respectively. Rabbits in treatment four (T ) were fed diet containing synthetic vitamin C and the fifth group (T ) were fed diet containing Baobab Fruit PulpMeal (BFPM). Rabbits were given access to feed and water ad libitum. All recommended managerial practices were duly observed.Microclimate parameters of ambient temperature (AT) and relative humidity (RH) of the rabbitry were taken daily from February through June. The values were used to calculate temperature-humidity index (THI). It was found that vitamin C and BFPM significantly (P<0.05) enhanced feed intake compared to the treatments with buffers. It was concluded that BFPM is more effective in ameliorating heat stress in rabbit production and can be used up to 5.5% inclusion level.

A review on vitamin E natural analogues and on the design of synthetic vitamin E derivatives as cytoprotective agents.

: Vitamin E, essential for human health, is widely used worldwide for therapeutic or dietary reasons. The differences in the metabolism and excretion of the multiple vitamin E forms are presented in this review. The important steps that influence the kinetics of each form and the distribution and processing of vitamin E forms by the liver are considered. The antioxidant as well as non-antioxidant properties of vitamin E forms are discussed. Finally, synthetic tocopherol and trolox derivatives, based on the design of multitarget directed compounds, are reviewed. It is demonstrated that selected derivatization of vitamin E or trolox structures can produce improved antioxidants, agents against cancer, cardiovascular and neurodegenerative disorders.

Vitamin P – Do Certain Polyphenolic IMPS Have a Vital Function?

In the 1930s, it was discovered that the ability of synthetic Vitamin C to treat scurvy was inferior to plant extracts containing Vitamin C. This observation led to the proposal of Vitamin P (permeability), as an essential phytochemical dietary nutrient. Subsequent attempts to isolate and characterize Vitamin P led to confusing and sometimes irreproducible results. Over the years several flavonoids and coumarins have been identified as having Vitamin P-like activity. Essentially all of these Vitamin P candidates were recently identified as IMPs (Invalid/Improbable/Interfering Metabolic Panaceas) in a NAPRALERT meta analysis. While the historic inability to define a single compound and specific mode of action led to general skepticism about the Vitamin P proposition, the more logical conclusion is that several abundant and metabolically labile plant constituents fill this essential role in human nutrition. This review of 100+ years of multilingual Vitamin P and C literature provides the rationales for this conclusion.

A Randomized Pilot Trial to Evaluate the Bioavailability of Natural versus Synthetic Vitamin B Complexes in Healthy Humans and Their Effects on Homocysteine, Oxidative Stress, and Antioxidant Levels

The vitamin B complex comprises 8 different water-soluble constituents that humans must sequester from the diet. This pilot study compared natural versus synthetic vitamin B complexes for their bioavailability, accumulation, and their impact on antioxidants, homocysteine levels, and oxidative stress. We conducted a double-blind randomized clinical trial with thirty healthy participants. They were randomly assigned to group N (natural) and group S (synthetic). Vitamin B was ingested daily for 6 weeks in the range of about 2.5 times above the recommended daily allowance. Blood samples were taken at baseline, 1.5 h, 4 h, 7 h (diurnal), 6 w (discontinuation of supplements), and 8 w (washout). Blood levels of thiamine (B1), riboflavin (B2), pyridoxine (B6), folic acid (B9), cobalamin (B12), homocysteine, total antioxidants, peroxidase activity, polyphenols, and total peroxides were determined. Compared to initial values, serum levels of each B vitamin increased at the end of the supplementation period: i.e., B1 (+23% N; +27% S), B2 (+14% N; +13% S), B6 (+101% N; +101% S), B9 (+86% N; +153% S), and B12 (+16% N) (p<0.05). Homocysteine (-13% N) decreased, while peroxidase activity (+41% S) and antioxidant capacity increased (+26% N). Short-term effects were already observed after 1.5 h for B9 (+238% N; +246% S) and after 4 h for vitamin B2 (+7% N; +8% S), B6 (+59% N; +51% S), and peroxidase activity (+58% N; +58% S). During the washout period, serum levels of B vitamins decreased except for thiamine and peroxidase activity, which increased further. This clinical pilot study revealed comparable bioavailability for both natural and synthetic B vitamins but did not show statistically noticeable differences between groups despite some favourable tendencies within the natural vitamin group, i.e., sustained effects for cobalamin and endogenous peroxidase activity and a decrease in homocysteine and oxidative stress levels.