Benjakul Extract

Benjakul, a traditional Thai formulation for cancer treatment, is composed of five plants. This study aimed to assess the cytotoxicity of Benjakul, its five plants, and its isolated compounds against non-small cell lung cancer (NSCLC) by the sulforhodamine B (SRB) assay.

Analyses of cell cycle and membrane asymmetry changes were performed with different fluorescent dyes and analyzed by flow cytometry in NCI-H226 cells. Activation of caspase-3 was measured using a caspase-3 colorimetric assay kit. The pan-caspase inhibitor Z-VAD-FMK was used in analyses of cell cycle and caspase-3 activity.

Benjakul exhibited cytotoxicity against NSCLC with IC50 between 5.56-5.64 μg/mL. Among its five ingredients, Benjakul displayed the highest selectivity with selectivity index values ranging from 2.93 to 6.88, with the exception of Plumbago indica, indicating its protective effects. Plumbagin and 6- shogaol displayed the highest cytotoxicity and underwent molecular studies in NCI-H226 cells. Flow cytometry analysis revealed that Benjakul and 6-shogaol dose-dependently induced G2/M phase arrest, and plumbagin dose-dependently induced S-G2/M phase arrest with the highest percentage in early incubation time (12-24 h). At the highest doses, Benjakul extract, 6-shogaol, and plumbagin time-dependently increased the population of sub-G1 apoptotic cells with the highest percentage in longer incubation time (60-72 h). Similarly, membrane asymmetry changes showed time-dependent increases in the percentage of early and late apoptotic cells. Moreover, the apoptosis-inducing effect of Benjakul, 6-shogaol, and plumbagin at the highest dose, via the caspase cascade was confirmed by time-dependent induction of caspase-3 activity, followed by its complete reduction and abolished sub-G1 peaks upon addition of Z-VAD-FMK.

Our findings demonstrated for the first time the effects of Benjakul and its compounds on S-G2/M or G2/M phase arrest and caspase-dependent apoptosis in lung cancer cells.

Benjakul (BJK) is a Thai traditional remedy consisting of five plants: Piper chaba Hunt., Piper sarmentosum Roxb., Piper interruptum Opiz., Plumbago indica Linn., and Zingiber officinale Roscoe. It is used as a first‐line drug to balance patient’s symptoms before other treatments. BJK ethanolic extract has been reported to show anti‐inflammatory activity through various mediators, e.g., nitric oxide, TNF‐α, IL‐1β, and IL‐6. Therefore, BJK could serve as a potential novel anti‐inflammatory herbal medicine. However, studies on prostaglandin E2 (PGE2), one of the key mediators in acute inflammation, and anti‐inflammation in animal models (in vivo) have not been done. This study investigated the anti‐inflammatory activity of BJK extract and some of its chemical compounds against PGE2 production in murine macrophage (RAW 264.7) cell line and two in vivo models of anti‐inflammatory studies. Ethanolic extract of BJK (BJK[E]) showed high inhibitory activity against PGE2 production with an IC50 value of 5.82 ± 0.10 μg/mL but its water extract (BJK[W]) was inactive. Two chemicals from BJK[E], i.e., plumbagin and myristicin, which served as biological markers, showed strong activity with IC50 values of 0.08 ± 0.01 and 1.80 ± 0.06 μg/mL, respectively. BJK[E] was administered both topically and orally to rats inhibited with inflammation induced by ethyl phenylpropiolate (rat ear edema model) and carrageenan (hind paw edema model). Moreover, the biological activity of BJK extract did not reduce after six‐month storage under accelerated condition (40°C, 75% RH). This indicated its stability and a 24‐month shelf‐life under normal condition. These results supported not only the use of BJK in Thai traditional medicine but also the possibility of further development of phytopharmaceutical products from BJK.