HPLC and GC analyses of in vitro-grown leaves of the cancer bush Lessertia (Sutherlandia) frutescens L. reveal higher yields of bioactive compounds

Abstract

Lessertia frutescens L., commonly known as cancer-bush, is a medicinally reputed plant species indigenous to southern Africa. Field leaf extracts of this species are known to exhibit many curative properties. However, little is known about the bioactive compounds that are present in in vitro leaf extracts and seed extracts. The objective of this study was to verify the presence of and quantify L-canavanine, gamma amino butyric acid (GABA), arginine and D-pinitol in the seeds, field leaves and in vitro leaves of L. frutescens using gas and liquid chromatography. Methanolic extracts of in vitro leaves, field leaves and seeds were used. MRM chromatograms were recorded for L-canavanine and arginine using tandem mass spectrometry. GC chromatograms were recorded for GABA and D-pinitol using gas chromatography. D-Pinitol was found to be most abundant and was 14.75 and 18.17 mg/g in in vitro and field leaf extracts respectively, followed by GABA (7.29 and 3.48 mg/g), arginine (7.08 and 0.35 mg/g) and L-canavanine (0.55 and 0.08 mg/g). In the seed extracts, GABA content was found to be the highest (1.69 mg/g) followed by L-canavanine (0.37 mg/g), then D-pinitol (0.25 mg/g), and arginine (0.02 mg/g). In vitro leaves had higher quantities of all compounds, except for D-pinitol. This study therefore highlights the potential of bulking in vitro leaves for the extraction of the medicinal compounds, L-canavanine and GABA.

Commercially Important Medicinal Plants of South Africa: A Review

“…Proline, L-asparagine, and alanine were the most abundant amino acids and collectively represent almost 60% of total amino acid content; however, not all samples contained all the amino acids. e content of L-canavanine, arginine, GABA, and D-pinitol in seeds, �eld leaves, and in vitro leaves of S. frutescens was quanti�ed by Shaik et al [158]. e results revealed that the secondary metabolites signi�cantly differed depending on the source.…”

Cytokinin-induced organogenesis in Lessertia (Sutherlandia) frutescens L. using hypocotyl and cotyledon explants affects yields of l-canavanine in shoots

“…These extracts are also reported to inhibit the action of human immunodeficiency virus (HIV) target enzymes (Hartnett et al 2005) and decrease cancerous cell growth (Stander et al 2009), which are purported to be the result of the action of L-canavanine. Research in our laboratory has shown that the yields of medicinal phytocompounds are higher in in vitro leaf extracts than in field leaf or seed extracts (Shaik et al 2010a). Rout et al (2000) reported that medicines derived from plant sources are popular worldwide and, therefore utilized as pharmaceuticals on the global scale.…”

Differential signaling involved in Sutherlandia frutescens-induced cell death in MCF-7 and MCF-12A cells

“…leaves, stems etc.) from which the extract is derived (Shaik et al, 2010). At this time, no single molecular pathway explaining the effects observed in studies investigating the therapeutic potential of S.…”

“…When taking into account the fact that a single pharmacologically active ingredient responsible for the varied effects of S. frutescens has not been isolated and the differing efficacy of ethanolic and aqueous extracts, it becomes apparent that the cumulative combination of the bioactive compounds in plant extracts (Shaik et al, 2010) must be responsible for the promising antiproliferative effects. The concentrations of each of the potentially therapeutic compounds is, to a large extent, dependent on the location (regional differences) and growth conditions (soil conditions, UV exposure etc.)…”

“…Research into the chemical constitution of the plant has shown that S. frutescens contains large amounts of amino acids (notably L-arginine and L-canavanine), pinitol, flavonol glycosides and triterpenoid saponins (Moshe et. al., 1998) (van Wyk and Albrecht, 2008) (Shaik et al, 2010). L-canavanine replaces the structurally related amino acid L-arginine during protein synthesis, leading to non-functional proteins.…”