Cat's claw oxindole alkaloid isomerization induced by common extraction methods

Abstract

Recebido em 31/8/12; aceito em 24/1/13; publicado na web em 14/5/13Cat's claw oxindole alkaloids are prone to isomerization in aqueous solution. However, studies on their behavior in extraction processes are scarce. This paper addressed the issue by considering five commonly used extraction processes. Unlike dynamic maceration (DM) and ultrasound-assisted extraction, substantial isomerization was induced by static maceration, turbo-extraction and reflux extraction. After heating under reflux in DM, the kinetic order of isomerization was established and equations were fitted successfully using a four-parameter Weibull model (R 2 > 0.999). Different isomerization rates and equilibrium constants were verified, revealing a possible matrix effect on alkaloid isomerization.

Catʼs Claw Oxindole Alkaloid Isomerization Induced by Cell Incubation and Cytotoxic Activity against T24 and RT4 Human Bladder Cancer Cell Lines

“…1S, Supporting Information). The mitraphylline (1) was converted to isomitraphylline (2) (trans D/E ring junction), and speciophylline (3), uncarine F (4), and pteropodine (5) were converted to isopteropodine (6) (cis D/E ring junction) similar to what has been previously observed from bark catʼs claw crude extract [14]. Likewise, isorhyncophylline (8) was isomerized to rhyncophylline (7).…”

“…Both POA and TOA contents were assayed by an HPLC-PDA method [14] using mitraphylline (1) (Phytolab, purity > 99%) as the external standard. Briefly, the analyses were performed employing an HPLC-PDA Proeminence (Shimadzu).…”

In vitro synergism of a water insoluble fraction of Uncaria tomentosa combined with fluconazole and terbinafine against resistant non-Candida albicans isolates

“…Briefly, contents and profiles of oxindole alkaloids (Kaiser et al. 2013b ), quinovic acid glycosides (Pavei et al. 2012 ), and low molecular weight polyphenols (Pavei et al.…”

Rapid determination of oxindole alkaloids in cat's claw by HPLC using ionic liquid‐based microwave‐assisted extraction and silica monolithic column

“…Some clinical trials have demonstrated that cat's claw preparations can alleviate osteoarthritis and rheumatoid arthritis (Rosenbaum, O'Mathuna, Chavez, & Shields, ); they also can be used as an adjuvant treatment for cancer (do Carmo Santos Araújo et al, ). Monoterpene oxindole alkaloids are the most prominent components in cat's claw and are also used as quality controls, for example, a tetracyclic oxindole alkaloid, namely rhynchophylline (RHY), and pentacyclic oxindole alkaloids, namely pteropodine (PTE), isomitraphylline (IMI) and isopteropodine (IPT) (Figure ; Kaiser, Verza, et al, ).…”

“…High‐performance liquid chromatography (HPLC) is by far the most popular method for the analysis of alkaloids in cat's claw. In the literature, the stationary phases used are based on particulate packing materials; however, they require separation times of 30 min or more owing to the problems of higher backpressures when flow rates are increased (Bertol, Franco, & Oliveira, ; Ganzera, Muhammad, Khan, & Khan, ; Kaiser, Dietrich, et al, ; Kaiser, Verza, , ; Montoro, Carbone, de Dioz Zuniga Quiroz, De Simone, & Pizza, ; Pilarski, Zieliński, Ciesiołka, & Gulewicz, ; Stuppner, Sturm, & Konwalinka, ). Monolithic columns represent an innovative type of column for rapid chromatographic separation (Rahim, Nofrizal, & Saad, ).…”