Antioxidant, Gastroprotective, Cytotoxic Activities and UHPLC PDA-Q Orbitrap Mass Spectrometry Identification of Metabolites in Baccharis grisebachii Decoction.

The decoction of the local plant Baccharis grisebachii is used as a digestive, gastroprotective, external cicatrizing agent and antiseptic in Argentine. A lyophilized decoction (BLD) from the aerial parts of this plant was evaluated regarding its anti-ulcer, antioxidant and cytotoxic activities and the bioactivities were supported by UHPLC-MS metabolome fingerprinting which revealed the presence of several small bioactive compounds. The antioxidant properties were evaluated by DPPH, TEAC, FRAP and lipoperoxidation inhibition in erythrocytes methods, and the antibacterial activity was evaluated according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The BLD showed a moderate free radical scavenging activity in the DPPH (EC50 = 106 µg/mL) and lipid peroxidation in erythrocytes assays (67%, at 250 µg/mL). However, the BLD had the highest gastroprotective effect at a dose of 750 mg/kg with a ninety-three percent inhibition of damage through a mechanism that involve NO and prostaglandins using the ethanol-induced gastric damage in a standard rat model. On the other hand, BLD does not induce cytotoxic changes on human tumor and no-tumor cell lines at the concentrations assayed. Regarding the metabolomic analysis, thirty-one compounds were detected and 30 identified based on UHPLC-OT-MS including twelve flavonoids, eleven cinnamic acid derivatives, one coumarin, one stilbene and two other different phenolic compounds. The results support that the medicinal decoction of Baccharis grisebachii is a valuable natural product with gastroprotective effects and with potential to improve human health that opens a pathway for the development of important phytomedicine products.

UHPLC-MS Metabolome Fingerprinting: The Isolation of Main Compounds and Antioxidant Activity of the Andean Species Tetraglochin ameghinoi (Speg.) Speg.

The seriated extracts of petroleum ether (PE-E), dichloromethane (DCM-E) and methanol extracts (MeOH-E) from the aerial parts of the native South American plant Tetraglochin ameghinoi (Rosaceae), were evaluated regarding their antioxidant and antibacterial activities. The antioxidant properties were evaluated by free radical scavenging methods (DPPH and TEAC), ferric-reducing antioxidant power (FRAP) and lipoperoxidation in erythrocytes (LP), while the antibacterial activity was performed against Gram-positive and Gram-negative bacteria according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The chemical and biological analyses of this plant are very important since this bush is currently used in traditional medicine as a cholagogue and digestive. The polar MeOH-E showed the highest antioxidant activities (17.70 µg/mL in the DPPH assay, 381.43 ± 22.38 mM TE/g extract in the FRAP assay, 387.76 ± 91.93 mg TE/g extract in the TEAC assay and 93.23 + 6.77% in the LP assay) and it was selected for chromatographic isolation of its components. These components were found to be four acetophenones, including the new phloracetophenone glucoside: 4',6',-dihydroxy-2'-O-(6″-acetyl)-ß-d-glucopyranosylacetophenone or IUPAC name: (6-(2-acetyl-3,5-dihydroxyphenoxy)-3,4,5-trihydroxytetrahydro-2H-pyran-2-yl)methyl acetate, whose structure was elucidated by NMR and MS methods. In addition, twenty-six compounds, including five of these acetophenone derivatives, two sugars, six flavonoids, eleven phenolic acids and two triterpenes, were identified based on UHPLC-OT-MS and PDA analysis on the MeOH-E. The results support the medicinal use of the plant.

Argentinean Andean propolis associated with the medicinal plant Larrea nitida Cav. (Zygophyllaceae). HPLC-MS and GC-MS characterization and antifungal activity.

The chemical profile and botanical origin of Andean Argentinian propolis were studied by HPLC-ESI-MS/MS and GC-MS techniques as well as the antifungal activity according to CLSI protocols. Dermatophytes and yeasts tested were strongly inhibited by propolis extracts (MICs between 31.25 and 125 µg/mL). The main antifungal compounds were: 3'methyl-nordihydroguaiaretic acid (MNDGA) 1, nordihydroguaiaretic acid (NDGA) 2 and a NDGA derivative 3, showing strong activity against Trichophyton mentagrophytes, T. rubrum and Microsporum gypseum (MICs between 15.6 and 31.25 µg/mL). The lignans 1 and 2 showed activities against clinical isolates of Candidas spp., Cryptococcus spp., T. rubrum and T. mentagrophytes (MICs and MFCs between 31.25 and 62.5 µg/mL). The lignan and volatile organic compounds (VOCs) profiles from propolis matched with those of exudates of Larrea nitida providing strong evidences on its botanical origin. These results support that Argentinian Andean propolis are a valuable natural product with potential to improve human health. Six compounds (1-6) were isolated from propolis for the first time, while compounds 1 and 3-6 were reported for first time as constituents of L. nitida Cav.

Essential oils of medicinal plants from the central andes of Argentina: chemical composition, and antifungal, antibacterial, and insect-repellent activities.

The antifungal, antibacterial, and insect-repellent activities of the essential oils (EOs) of Acantholippia seriphioides, Artemisia mendozana, Gymnophyton polycephalum, Satureja parvifolia, Tagetes mendocina, and Lippia integrifolia, collected in the Central Andes area, province of San Juan, Argentina, were investigated. The dermatophytes Microsporum gypseum, Trichophyton mentagrophytes, and T. rubrum were inhibited by the EOs of G. polycephalum, L. integrifolia, and S. parvifolia, with minimum inhibitory concentrations (MICs) between 31.2 and 1000 µg/ml. Moreover, all EOs presented moderate activity against the bacteria tested, and the L. integrifolia and G. polycephalum EOs showed excellent repellent properties against Triatoma infestans, the Chagas disease vector, with repellency values between 60 and 100%. The A. seriphioides, G. polycephalum, and L. integrifolia EOs, obtained by hydrodistillation, were characterized by GC-FID and GC/MS analyses. The highest number of components (40) was identified in L. integrifolia EO, which, along with that of A. seriphioides, contained important amounts of oxygenated monoterpenes (44.35 and 29.72%, resp.). Thymol (27.61%) and carvacrol (13.24%) were the main components of A. seriphioides EO, and borneol, lippifoli-1(6)-en-5-one, and terpinen-4-ol (>8.5%) were the principal compounds of L. integrifolia EO. These results support the idea that oxygenated monoterpenes are the bioactive fractions of the EOs. Finally, the study shows that these Andean species might be used to treat superficial fungal infections and to improve the local Chagas disease situation by vector-control.

Antifungal activity of Zuccagnia punctata Cav.: evidence for the mechanism of action.

Petroleum ether and dichloromethane extracts of fruits, aerial parts and exudate of Zuccagnia punctata Cav. (Fabaceae) showed moderate antifungal activities against the yeasts C. albicans, S. cerevisiae and C. neoformans (MICs: 62.5 - 250 microg/mL) and very strong antifungal activities against the dermatophytes M. gypseum, T. rubrum and T. mentagrophytes (MICs: 8 - 16 microg/mL) thus supporting the ethnopharmacological use of this plant. Antifungal activity-directed fractionation of active extracts by using bioautography led to the isolation of 2',4'-dihydroxy-3'-methoxychalcone (1) and 2',4'-dihydroxychalcone (2) as the compounds responsible for the antifungal activity. Second-order studies included MIC (80), MIC (50) and MFC of both chalcones in an extended panel of clinical isolates of the most sensitive fungi, and also comprised a series of targeted assays. They showed that the most active chalcone 2 is fungicidal rather than fungistatic, does not disrupt the fungal membranes up to 4 x MFC and does not act by inhibiting the fungal cell wall. So, 2',4'-dihydroxychalcone would act by a different mechanism of action than the antifungal drugs in current clinical use, such as amphotericin B, azoles or echinocandins, and thus appears to be very promising as a novel antifungal agent.