Background: Herb-drug interactions (HDIs) resulting from concomitant use of herbal products with clinical drugs may cause adverse reactions. Organic anion transporter 1 (OAT1) and 3 (OAT3) are highly expressed in the kidney and play a key role in the renal elimination of substrate drugs. So far, little is known about the herbal extracts that could modulate OAT1 and OAT3 activities.Methods: HEK293 cells stably expressing human OAT1 (HEK-OAT1) and OAT3 (HEK-OAT3) were established and characterized. One hundred seventy-two extracts from 37 medicinal and economic plants were prepared. An initial concentration of 5 µg/ml for each extract was used to evaluate their effects on 6-carboxylfluorescein (6-CF) uptake in HEK-OAT1 and HEK-OAT3 cells. Concentration-dependent inhibition studies were conducted for those extracts with more than 50% inhibition to OAT1 and OAT3. The extract ofJuncus effusus, a well-known traditional Chinese medicine, was assessed for its effect on thein vivopharmacokinetic parameters of furosemide, a diuretic drug which is a known substrate of both OAT1 and OAT3.Results: More than 30% of the plant extracts at the concentration of 5 µg/ml showed strong inhibitory effect on the 6-CF uptake mediated by OAT1 (61 extracts) and OAT3 (55 extracts). Among them, three extracts for OAT1 and fourteen extracts for OAT3 were identified as strong inhibitors with IC₅₀values being <5 µg/ml.Juncus effususshowed a strong inhibition to OAT3in vitro, and markedly altered thein vivopharmacokinetic parameters of furosemide in rats.Conclusion: The present study identified the potential interactions of medicinal and economic plants with human OAT1 and OAT3, which is helpful to predict and to avoid potential OAT1- and OAT3-mediated HDIs.

A bioactivity guided program exploring the interaction of phytochemicals in the entire plant Primula macrocalyx with the organic anion transporters (OAT1 and OAT3) and microorganisms led to the elucidation of ten known flavones (1–4, 6–10, 12) and two previously undescribed flavones (5, 11). The structures of the compounds were determined by extensive analysis of spectroscopic data, as well as by comparison with data from previous reports. Two known flavones (9, 12) are reported for the first time from the family Primulaceae. All compounds were evaluated for inhibition of OAT1 and OAT3. Six flavones (2, 3, 6–8, 12) showed potent inhibitory activity on OAT1, while seven flavones (2, 3, 6–9, 12) showed marked inhibitory activity on OAT3, with IC₅₀ ≤ 10.0 µM. Antimicrobial activities of crude fractions against sixteen microorganisms were tested to give a target yeast strain Candida rugosa for further evaluation of MICs on the isolates. Three flavones (7, 8, 12) showed marked antifungal activity with MIC < 2.0 µM. To our knowledge, this study is the first to evaluate these flavones as inhibitors of the OAT1 and OAT3, and as antifungal agents.

The emergence of drug resistant microbes over recent decades represents one of the greatest threats to human health; the resilience of many of these organisms can be attributed to their ability to produce biofilms. Natural products have played a crucial role in drug discovery, with microbial natural products in particular proving a rich and diverse source of antimicrobial agents. During antimicrobial activity screening, the strain Pseudomonas mosselii P33 was found to inhibit the growth of multiple pathogens. Following chemical investigation of this strain, pseudopyronines A-C were isolated as the main active principles, with all three pseudopyronines showing outstanding activity against Staphylococcus aureus. The analogue pseudopyronine C, which has not been well-characterized previously, displayed sub-micromolar activity against S. aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. Moreover, the inhibitory abilities of the pseudopyronines against the biofilms of S. aureus were further studied. The results indicated all three pseudopyronines could directly reduce the growth of biofilm in both adhesion stage and maturation stage, displaying significant activity at micromolar concentrations.

Effective neuroblastoma (NB) treatments are still limited despite treatment options available today. Therefore, this study attempted to identify novel plant extracts that have anticancer effects. Cytotoxicity and increased intracellular calcium levels were determined using the Sulforhodamine B (SRB) assay and Fluo4-AM (acetoxymethyl) staining and fluorescence microscopy in NB cells in order to screen a library of plant extracts. The current study examined the anticancer effects of a dichloromethane extract from Scrophularia orientalis L. (Scrophulariaceae), a plant that has been used in Traditional Chinese Medicine. This extract contained highly potent agents that significantly reduced cell survival and increased calcium levels in NB cells. Further analysis revealed that cell death induced by this extract was associated with intracellular calcium release, opening of the MPTP, caspase 3- and PARP-cleavage suggesting that this extract induced aberrant calcium signaling that resulted in apoptosis via the mitochondrial pathway. Therefore, agents from Scrophularia orientalis may have the potential to lead to new chemo-therapeutic anticancer drugs. Furthermore, targeting intracellular calcium signaling may be a novel strategy to develop more effective treatments for NB.