Leshweni Jeremia Shai

Aflatoxin biomarkers in hair may facilitate long-term exposure studies.

Aflatoxins are highly toxic fungal metabolites produced by some members of the Aspergillus species. They are low molecular weight lipophilic compounds that are easily absorbed from the gastrointestinal tract. They contaminate most staple foods, including maize, peanuts, peanut butter and sorghum mainly in the tropics where hot and humid conditions promote fungal growth. Absorbed aflatoxins are metabolized by the cytochrome P450 enzyme system in the liver into toxic metabolites. Aflatoxin B (AFB)1 is the most toxic, carcinogenic and mutagenic naturally occurring toxin. Aflatoxin exposure assessment has been traditionally achieved through food use frequency questionnaires and laboratory analysis of food samples. However, estimation of individual exposure to aflatoxins based on these methods may not be accurate. The use of aflatoxin biomarkers in urine and blood for use in exposure studies has emerged in more recent times. However, the current biomarkers (e.g., AFB‐N7‐guanine and AFB1‐albumin adduct) in use have a short half‐life and are only practically useful to indicate levels over 24 h–3 months post‐exposure. There is therefore an immediate need to study and evaluate alternative biomarkers in non‐conventional matrices such as hair and nails. Hair analysis revealed considerable interest in forensic analysis particularly in the detection of drugs of abuse where it has emerged as a sensitive and specific technique complementary to blood and urinalysis. This article provides an overview of aflatoxins, current aflatoxin biomarkers and proposes the use of hair as a potential matrix for biomarkers of long‐term aflatoxin exposure. Copyright

Investigation of the mechanism of anti-inflammatory action and cytotoxicity of a semipurified fraction and isolated compounds from the leaf of Peltophorum africanum (Fabaceae)

Peltophorum africanum extracts have been shown to possess many important medicinal benefits, including anti-inflammatory and antiviral activities. However, the mechanism of action is poorly understood. The mechanism of anti-inflammatory action was determined by measuring the synthesis of cytokines in lipopolysaccharide (LPS) stimulated RAW 264.7 macrophage cells in vitro. Compound 1 (CP1), compound 2 (CP2), and fraction F3.3.0 (F3.3.0) significantly reduced the synthesis of interleukin 1β (IL-1β) from RAW 264.7 cells (1.18, 1.32, and 0.92 ng/mL), respectively. Similarly, CP1, CP2, and F3.3.0 inhibited the production of IL-2 and tumor necrosis factor–α (TNF-α) by RAW 264.7 cells (0.41, 0.60, 0.74 and 0.11, 0.27, 0.24 ng/mL, respectively. In addition, CP1 and CP2 had lower cytotoxicity toward RAW 264.7 cells, with CP2 indicating the lowest cytotoxicity (LD50 = 207.88 µg/mL). The mechanism of action was found to be via the inhibition of pro-inflammation cytokines (IL-1 β and TNF-α). This observation may support the use of P africanum to treat pain-related conditions.