Estrogenic and progestagenic effects of extracts of Justicia pectoralis Jacq., an herbal medicine from Costa Rica used for the treatment of menopause and PMS

Abstract

Objectives: To investigate the biological activities of Justicia pectoralis Jacq. (Acanthaceae), an herbal medicine used in Costa Rica (CR) for the management of menopausal symptoms and dysmenorrhea.

Study design: The aerial parts of J. pectoralis were collected, dried and extracted in methanol. To establish possible mechanisms of action of JP for the treatment of menopausal symptoms, the estrogenic and progesterone agonists, and antiinflammatory activities were investigated.

Main outcome measures: The methanol extract (JP-M) was tested in ER and PR binding assays, a COX-2 enzyme inhibition assay, the ERbeta-CALUX assay in U2-OS cells, as well as reporter and endogenous gene assays in MCF-7 K1 cells.

Results: The JP-M extract inhibited COX-2 catalytic activity (IC(50) 4.8 microg/mL); bound to both ERalpha and ERbeta (IC(50) 50 microg/mL and 23.1 microg/mL, respectively); induced estrogen-dependent transcription in the ERbeta-CALUX; and bound to the progesterone receptor (IC(50) 22.8 microg/mL). The extract also modulated the expression of endogenous estrogen responsive genes pS2, PR, and PTGES in MCF-7 cells at a concentration of 20 microg/mL. Activation of a 2 ERE-construct in transiently transfected MCF-7 cells by the extract was inhibited by the estrogen receptor antagonist ICI 182,780, indicating that the effects were mediated through the estrogen receptor. Finally, the extract weakly enhanced the proliferation of MCF-7 cells, however this was not statistically significant as compared with DMSO controls.

Conclusions: Extracts of J. pectoralis have estrogenic, progestagenic and anti-inflammatory effects, and thus have a plausible mechanism of action, explaining its traditional use for menopause and PMS.

Figure 1

Results of the ER-CALUX® reporter gene assay demonstrating the ability of the JP-M extract to induce transcription of an estrogen responsive luciferase reporter gene through activation of ERβ in stably transfected U2-OS cells. Data represent the mean ± SD of three separate experiments performed in triplicate.

Figure 2

The ER antagonist ICI 182780 specifically blocks the induction of luciferase activity by JP-M through ERα in MCF-7 cells transiently transfected with a pERE-luciferase plasmid. Cells were treated with 10 nM E2 or 10 nM E2 + 1 µM ICI 182780 or 20 µg/ml JP-M or 20 µg/ml JP-M + 1 µM ICI 182780 to assess induction. Relative luciferase units were measured by luminometer. Results are expressed as fold induction above control (vehicle solvent). Abbreviations: E2 = 17β-estradiol; JP-M = Justicia pectoralis; ICI = ICI 182,780. Data represent the mean ± SD of three separate experiments performed in triplicate.

Figure 3

Results of RT-PCR analysis of endogenous estrogen responsive genes in MCF-7 cells after treatment with plant extracts (20 µg/ml). Data is represented as fold increase in mRNA above control for (3) pS2, (4) PR, (5) PTGES. Extracts are abbreviated: JP-M = Justicia pectoralis. MCF-7 cells were treated with the JP-M extract (20 µg/ml) + E2 (10 nM) to assess synergistic or antagonistic effects. Data represent the mean ± SD of three separate experiments performed in triplicate.

Figure 4

Results of RT-PCR analysis of endogenous estrogen responsive genes in MCF-7 cells after treatment with plant extracts (20 µg/ml). Data is represented as fold increase in mRNA above control for (3) pS2, (4) PR, (5) PTGES. Extracts are abbreviated: JP-M = Justicia pectoralis. MCF-7 cells were treated with the JP-M extract (20 µg/ml) + E2 (10 nM) to assess synergistic or antagonistic effects. Data represent the mean ± SD of three separate experiments performed in triplicate.

Figure 5

Results of RT-PCR analysis of endogenous estrogen responsive genes in MCF-7 cells after treatment with plant extracts (20 µg/ml). Data is represented as fold increase in mRNA above control for (3) pS2, (4) PR, (5) PTGES. Extracts are abbreviated: JP-M = Justicia pectoralis. MCF-7 cells were treated with the JP-M extract (20 µg/ml) + E2 (10 nM) to assess synergistic or antagonistic effects. Data represent the mean ± SD of three separate experiments performed in triplicate.

Figure 6

Results of MCF-7 cell proliferation data after treatment with DMSO control, E2 (10 nM) or JP-M (20 µg/ml).

Figure 7

Stuctures of the two coumarins, coumarin and umbelliferone isolated from Justicia pectoralis.