A hydroalcoholic extract of lime ( Citrus aurantifolia) leaves has been developed in Cuba to be used as a nutritional supplement and phytomedicine in the form of tincture (TLL). A HPLC-PDA-ESI/MS/MS method has been used for the comprehensive analysis of C-glycosyl flavones in TLL. Six C-glycosyl flavones were characterized and, to confirm the proposed structures and to elucidate the nature of the sugar units, a preparative procedure was applied, and isolated compounds were characterized by NMR. Apigenin-6,8-di-C-beta-D-glucopyranoside (vicenin II) (1), diosmetin-6,8-di- C-beta- d-glucopyranoside (2), apigenin-8-C-beta-D-glucopyranoside (vitexin) (3), apigenin-8-C-[alpha-L-arabinopyranosyl-(1-->6)]-O-beta-D-glucopyranoside (4), apigenin-6-C-[alpha-l-arabinopyranosyl-(1-->6)]-O-beta-D-glucopyranoside (5). and apigenin-6-C-beta-D-glucopyranoside (isovitexin) (6) were identified in TLL and quantified by HPLC-PDA. Compounds 4 and 5 were two new arabinosyl derivatives of vitexin and isovitexin. Inhibitor effect of TLL on platelet aggregation induced by physiological agonists of platelets was evaluated in human plasma. TLL inhibited significantly ADP and epinephrine-induced platelet aggregation in a concentration-dependent manner (IC 50=0.40 and 0.32 mg/mL, respectively).

The phytochemical profile of a hydroalcoholic extract of Citrus aurantium var. amara L. peel, used as herbal medicine, was characterized by HPLC-PDA-MS. Two di-C-glycosyl flavones (vincenin II and diosmetin 6,8-di-C-glucoside), a series of flavones (luteolin 7-O-neohesperidoside, rhoifolin, and neodiosmin), and flavanone (neoeriocitrin, naringin, and neohesperidin) 7-O-neohesperidosides and two methoxyflavones (nobiletin and tangeretin), commonly present in Citrus, were identified. Furthermore, brutieridin and melitidin, two 3-hydroxy-3-methylglutaryl flavanone glycosides, were also characterized along with rhoifolin 4'-glucoside and three coumarins (8,3'-β-D-glucopyranosyloxy-2'-hydroxy-3'-methylbutyl-7-methoxycoumarin, merazin hydrate, and isomerazin). A preparative isolation procedure followed by NMR spectroscopy confirmed the proposed structures of the major flavonoids and identified the coumarins. The phenolic content was found to be 14.8 mg mL(-1), and naringin and neohesperidin were the compounds present in the highest concentration (3.6 and 2.6 mg mL(-1)). The extract of C. aurantium peel inhibited significantly (p < 0.05) both histamine- and dextran-induced edema in rats in a concentration-dependent manner (IC(50) = 119.6 and 118.3 mg kg(-1), respectively), providing evidence for the therapeutic use of C. aurantium var. amara peel.

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Wendtia calycina (Griseb.) Griseb., Vivianiaceae, is a Paraguayan herbaceous plant commonly known as burrito. Our previous study indicated that burrito leaves are a very good source of phenylpropanoid glycosides, principally verbascoside. From W. calycina leaves, a standardized, water-soluble extract rich in phenylpropanoid glycosides (WSE) has been developed on an industrial scale to be used as a food supplement, cosmetic, phytomedicine, and ingredient of different formulations. In this study, we investigated the effect of the WSE on human platelet aggregation in vitro induced by adenosine diphosphate (ADP), epinephrine (EPN), collagen (COL) or arachidonic acid (AA). WSE, concentration-dependently, inhibited ADP and EP-induced human platelet aggregation (IC50 were 0.82±0.15 mg/mL and 0.41±0.02 mg/mL, respectively). It did not inhibit collagen-induced platelet aggregation, thus suggesting a selectivity for the ADP-induced platelet activation pathways.

Two vitamins, ascorbic acid (AA) and pyridoxine have been suggested by others as useful drugs for the treatment of bronchial asthma, although the views concerning AA or controversial. We have tested both vitamins in some models of histamine release and experimental anaphylaxis. AA does not inhibit mast cell degranulation induced by phospholipase A and histamine release from isolated rat mast cells induced by compound 48/80 or antigen (egg albumin). On the contrary, in the latter tests pyridoxine exerts inhibition in a range of concentrations from 10(-3)-10(-2) M. We conclude: 1. There is no experimental basis for considering ascorbic acid as a prophylactic antiasthmatic drug as is disodium cromoglycate. 2. Pyridoxine must receive additional basic and clinical investigations in this field.