Agastaquinone, a new cytotoxic diterpenoid quinone from Agastache rugosa

A review of natural products and small-molecule therapeutics acting on central nervous system malignancies: Approaches for drug development, targeting pathways, clinical trials, and challenges

In 2021, the World Health Organization released the fifth edition of the central nervous system (CNS) tumor classification. This classification uses histopathology and molecular pathogenesis to group tumors into more biologically and molecularly defined entities. The prognosis of brain cancer, particularly malignant tumors, has remained poor worldwide, approximately 308,102 new cases of brain and other CNS tumors were diagnosed in the year 2020, with an estimated 251,329 deaths. The cost and time-consuming nature of studies to find new anticancer agents makes it necessary to have well-designed studies. In the present study, the pathways that can be targeted for drug development are discussed in detail. Some of the important cellular origins, signaling, and pathways involved in the efficacy of bioactive molecules against CNS tumorigenesis or progression, as well as prognosis and common approaches for treatment of different types of brain tumors, are reviewed. Moreover, different study tools, including cell lines, in vitro, in vivo, and clinical trial challenges, are discussed. In addition, in this article, natural products as one of the most important sources for finding new chemotherapeutics were reviewed and over 700 reported molecules with efficacy against CNS cancer cells are gathered and classified according to their structure. Based on the clinical trials that have been registered, very few of these natural or semi-synthetic derivatives have been studied in humans. The review can help researchers understand the involved mechanisms and design new goal-oriented studies for drug development against CNS malignancies.

Agastache Species: A Comprehensive Review on Phytochemical Composition and Therapeutic Properties

The Agastache genus is part of the Lamiaceae family and is native to North America, while one species, Agastache rugosa (A. rugosa), is native to East Asia. A review on the phytochemistry and bioactivity of Agastache genus was last performed in 2014. Since then, a lot of progress has been made on the characterization of the phytochemical and pharmacological profiles of Agastache species. Thus, the purpose of this paper is to present a summary of the findings on the phytochemistry and biological effects of several Agastache species, including both extracts and essential oil characterization. We performed a comprehensive search using PubMed and Scopus databases, following PRISMA criteria regarding the study selection process. The available data is focused mainly on the description of the chemical composition and bioactivity of A. rugosa, with fewer reports referring to Agastache mexicana (A. mexicana) and Agastache foeniculum (A. foeniculum). Agastache species are characterized by the dominance of flavonoids and phenolic acids, as well as volatile compounds, particularly phenylpropanoids and monoterpenes. Moreover, a series of pharmacological effects, including antioxidant, cytotoxic, antimicrobial, anti-atherosclerotic, and cardioprotective properties, have been reported for species from the Agastache genus.

Changes in Human Electroencephalographic Activity in Response to Agastache rugosa Essential Oil Exposure

Agastache rugosa (Korean mint) is an important medicinal and aromatic plant and its aerial parts have a pleasant fragrance. A. rugosa leaves are used as an ingredient in salads and soups for enhancing the aroma and taste of foods in Korea. However, there is no report on the influence of the aroma of A. rugosa on human psychophysiological activity. Therefore, the present study aimed to investigate the effect of exposure to the essential oil of Korean A. rugosa on human electroencephalographic (EEG) activity. The essential oil of A. rugosa was isolated using steam distillation extraction and its composition was determined by gas chromatography and mass spectrometry (GC-MS) analysis. In the EEG study, 38 healthy volunteers (19 men and 19 women) participated. The EEG readings were analyzed for 25 EEG indices from 29 electrodes placed on the scalp according to the international 10-20 system. The major component in the essential oil of A. rugosa was estragole (89.49%) followed by D-limonene (3.40%), menthone (1.80%), and pulegone (1.86%). In the EEG study, significant decreases in absolute theta (AT) and relative theta (RT) power spectra were observed during the exposure to A. rugosa essential oil when compared to that of no odor exposure. Whereas relative alpha (RA), relative slow alpha (RSA), spectral edge frequency 50% (SEF50), and spectral edge frequency 50% of alpha (ASEF) power spectra values significantly increased. These results reveal that the EEG power spectra changes incurred during the exposure to the essential oil of A. rugosa may be associated with the enhancement of freshness and concentration states of the human brain.

Chemical Constituents from the Aerial Parts of Agastache rugosa and Their Inhibitory Activities on Prostaglandin E2 Production in Lipopolysaccharide-Treated RAW 264.7 Macrophages

A new flavone glucoside, acacetin-7-O-(3″-O-acetyl-6″-O-malonyl)-β-d-glucopyranoside (1), two new phenolic glucosides, (3R,7R)-tuberonic acid-12-O-[6'-O-(E)-feruloyl]-β-d-glucopyranoside (14) and salicylic acid-2-O-[6'-O-(E)-feruloyl]-β-d-glucopyranoside (15), and two new phenylpropanoid glucosides, chavicol-1-O-(6'-O-methylmalonyl)-β-d-glucopyranoside (17) and chavicol-1-O-(6'-O-acetyl)-β-d-glucopyranoside(18), as well as 26 known compounds, 2-13, 16, and 19-31, were isolated from the aerial parts of Agastache rugose. The structures of the new compounds were established by spectroscopic/spectrometric methods such as HRESIMS, NMR, and ECD. The anti-inflammatory effect of the isolated compounds was evaluated by measuring their inhibitory activities on prostaglandin E₂ (PGE₂) in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages. New compounds 1, 15, 17, and 18 inhibited LPS-induced PGE₂ production with IC₅₀ values of 16.8 ± 0.8, 33.9 ± 4.8, 14.3 ± 2.1, and 48.8 ± 4.4 μM, respectively. Compounds 5, 7, 9-11, 13, 19, 20, 22, and 27-30 showed potent inhibitory activities with IC₅₀ values of 1.7-8.4 μM.

Immunomodulatory Effects of Diterpene Quinone Derivatives from the Roots of Horminum pyrenaicum in Human PBMC

Several phytochemicals were shown to interfere with redox biology in the human system. Moreover, redox biochemistry is crucially involved in the orchestration of immunological cascades. When screening for immunomodulatory compounds, the two interferon gamma- (IFN-γ-) dependent immunometabolic pathways of tryptophan breakdown via indoleamine 2,3-dioxygenase-1 (IDO-1) and neopterin formation by GTP-cyclohydrolase 1 (GTP-CH-I) represent prominent targets, as IFN-γ-related signaling is strongly sensitive to oxidative triggers. Herein, the analysis of these pathway activities in human peripheral mononuclear cells was successfully applied in a bioactivity-guided fractionation strategy to screen for anti-inflammatory substances contained in the root of Horminum (H.) pyrenaicum L. (syn. Dragon's mouth), the only representative of the monophyletic genus Horminum. Four abietane diterpene quinone derivatives (horminone, 7-O-acetylhorminone, inuroyleanol and its 15,16-dehydro-derivative, a novel natural product), two nor-abietane diterpene quinones (agastaquinone and 3-deoxyagastaquinone) and two abeo 18 (4 → 3) abietane diterpene quinones (agastol and its 15,16-dehydro-derivative) could be identified. These compounds were able to dose-dependently suppress the above mentioned pathways with different potency. Beside the description of new active compounds, this study demonstrates the feasibility of integrating IDO-1 and GTP-CH-I activity in the search for novel anti-inflammatory compounds, which can then be directed towards a more detailed mode of action analysis.

Chemical constituents and coagulation activity of Agastache rugosa

Background

In the Chinese traditional medicine, plant of Agastache rugosa (Fisch. & C.A. Mey.) Kuntze (A. rugosa) has been used to treat nausea, vomiting and dispel damp. However, currently, few reports about the chemical constituents, especially the non-volatile components of A. rugosa are available.

Methods

Through separation with various column chromatographies to elucidate the chemical constituents of A. rugosa, the biological activities of the major constituents were investigated. The extracts and main constituents of A. rugosa were evaluated for their anticoagulant effects by assaying the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and fibrinogen (FIB) in vitro.

Results

Seven known compounds (namely compounds 1–7) were isolated from the aerial parts of A. rugosa. They were identified as methyl hexadecanoate (1), β-sitosterol (2), acacetin (3), ursolic acid (4), apigenin (5), protocatechuic acid (6) and tilianin (7), respectively. Compounds 1 and 6 were isolated from the genus Agastache for the first time, and compound 4 was obtained from the plants for the first time. The results showed that the extract of A. rugosa had a significant procoagulant activity by shortening the time of PT (P < 0.001) and increasing FIB content (P < 0.001), as compared with Vitamin K₁. While its major constituents acacetin and tilianin exhibited significant anticoagulant activities by prolonging the times of PT, APTT, TT and reducing FIB content (P < 0.001), as compared with blank control group.

Conclusions

The total extract of A. rugosa possessed significant procoagulant activity, while its main components, acacetin and tilianin possessed significant anticoagulant activities. Further investigation should be pursued to find out the bioactivity components responsible for the procoagulant action of the plant.

Therapeutic efficacy of Traditional Chinese medicine, "Kuan-Sin-Yin", in patients undergoing chemotherapy for advanced colon cancer - A controlled trial

BACKGROUND

Traditional Chinese Medicine (TCM) has been used increasingly as complementary medicine in cancer care. Kuan-Sin-Yin (KSY) is a TCM decoction containing seven herbs known to cause immunomodulation or anticancer activity, and which are associated with the TCM concept of Qi and energy supply. Kuan-Sin-Yin has cytostatic effects on cancer cells in animal models.

OBJECTIVE

The aim of this study is to evaluate the level of improvement in meridian energy and heart-rate variability (HRV) and to assess whether these observations are compatible with TCM theory.

METHOD

A non-randomized controlled trial was designed with monitoring of the meridian electro-conductivity and heart-rate variability (HRV) to compare the efficacy of Kuan-Sin-Yin in the control and experimental groups. 52 patients were enrolled in this study. We also measured cancer-related symptoms and quality of life as secondary outcomes.

RESULTS

We found that colon cancer patients who received KSY as complementary therapy benefitted with enhancement of meridian energy (Yin meridian: 27.90:35.45μA; p=0.014; Yang meridian: 27.09:33.55μA; p=0.024) and increases in HRV activity (78.40:129.04ms; SDNN: p=0.001) and parasympathetic tone(HF:1644.80:3217.92 ms²; p=0.003; RMMSD:99.76:164.52ms; p=0.002). Cancer-related symptoms decreased (ECOG>1:46.2:7.7%; p=0.0001), and quality of life (KSY group: PCS 35.46:42.12, p=0.0001; MCS: 44.50:47.55, p=0.209) was improved with statistical significance.

CONCLUSIONS

The correlation of positive results reflected in meridian energy and HRV activity confirms the positive role of complementary medicine of Kuan-Sin-Yin in cancer care.

Phytochemistry and bioactivity of aromatic and medicinal plants from the genus Agastache (Lamiaceae)

Agastache is a small genus of Lamiaceae, comprising 22 species of perennial aromatic medicinal herbs. In this article, we review recent advances in phytochemical, pharmacological, biotechnological and molecular research on Agastache. The phytochemical profile of all Agastache species studied to date is generally similar, consisted of two main metabolic classes-phenylpropanoids and terpenoids. In the relatively variable essential oils, most populations of different Agastache species contain over 50 % of a phenylallyl compound-estragole. Also, other volatile compounds (methyleugenol, pulegone, menthone, isomenthone and spathulenol) were reported in various proportions. Major non-volatile metabolites belong to phenolic compounds, such as caffeic acid derivatives, especially rosmarinic acid as well as several flavones and flavone glycosides like acacetin, tilianin, agastachoside, and a rare dimeric malonyl flavone (agastachin). Two unique lignans-agastenol and agastinol-were also isolated. Terpenoids include triterpenoids of oleanane-type (maslinic acid, oleanolic acid and β-amyrin), ursane-type (ursolic acid, corosolic acid and α-amyrin), and typical plant sterols, as well as abietane-type oxidized diterpenes (e.g., agastaquinone, agastol, and others). The bioactivity of various extracts or individual compounds in vitro and in vivo include antimicrobial, antiviral and anti-mutagenic activity, cytotoxic activity to cancer cell lines, and anti-nociceptive, anti-inflammatory, anti-atherogenic, antioxidant as well as biocidal activity to several foodstuff pests. Biotechnological and molecular studies have focused on in vitro propagation and enhancing the biosynthesis of bioactive metabolites in cell or organ cultures, as well as on the expression of genes involved in phenolic biosynthesis.

Accumulation of tilianin and rosmarinic acid and expression of phenylpropanoid biosynthetic genes in Agastache rugosa

Korean mint (Agastache rugosa), a perennial, medicinal plant of the Labiatae family, has many useful constituents, including monoterpenes and phenylpropanoids. Among these, tilianin and rosmarinic acid, 2 well-known natural products, have many pharmacologically useful properties. Chalcone synthase (CHS) and chalcone isomerase (CHI) catalyze the first and second committed steps in the phenylpropanoid pathway of plants, leading to the production of tilianin. In this study, cDNAs encoding CHS (ArCHS) and CHI (ArCHI) were isolated from A. rugosa using rapid amplification of cDNA ends (RACE)-PCR. Amino acid sequence alignments showed that ArCHS and ArCHI shared high sequence identity and active sites with their respective orthologous genes. Quantitative real-time PCR analysis was used to determine the expression levels of genes involved in tilianin and rosmarinic acid biosyntheses in the flowers, leaves, stems, and roots of A. rugosa. High-performance liquid chromatography (HPLC) revealed that the accumulation pattern of tilianin matched the expression patterns of ArCHS and ArCHI in different organs of A. rugosa. Moreover, acacetin, the precursor of tilianin, also demonstrated an accumulation pattern congruent with the expression of these 2 genes. The transcription levels of ArPAL, ArC4H, and Ar4CL were the highest in the leaves or flowers of the plant, which also contained a relatively high amount of rosmarinic acid. However, the roots showed a significant content of rosmarinic acid, although the transcription of ArPAL, ArC4H, and Ar4CL were low. The findings of our study support the medicinal usefulness of A. rugosa and indicate targets for increasing tilianin and rosmarinic acid production in this plant.

Inhibitory effects of quinones on RNase H activity associated with HIV-1 reverse transcriptase

In an effort to develop new drugs preventing the growth of human immunodeficiency virus (HIV), we developed an in vitro assay method of ribonuclease H (RNase H) activity associated with reverse transcriptase (RT) from HIV-1. Some naphthoquinones, such as 1,4-naphthoquinone (1), vitamin K(3) (2), juglone (3) and plumbagin (6), moderately inhibited RNase H activity, and others, including naphthazarin (5) and shikonins (8-9, 18-23), showed weak inhibition. Diterpenoid quinones, tanshinones (24-28), had also moderate inhibition against RNase H activity. Of these quinones, compound 1 showed the most potent inhibition on RNase H activity with a 50% inhibitory concentration (IC(50)) of 9.5 microM, together with moderate inhibition against RNA-dependent and DNA-dependent DNA polymerase (RDDP and DDDP) activities with IC(50) values of 69 and 36 microM, respectively. Compounds 3 and 5 showed significant inhibition against RDDP (IC(50) = 8 and 10 microM, respectively) and DDDP (IC(50) = 5 and 7 microM, respectively) activities. The structure-activity relationship of the naphthoquinones suggested that non-hydroxylated naphthoquinones (1 and 2) showed significant inhibition of RNase H activity, whereas 5-hydroxylated naphthoquinones (3 and 5) showed potent inhibition against RDDP and DDDP activities.

HIV integrase inhibitory activity of Agastache rugosa

We have been screening anti-HIV integrase compounds from Korean medicinal plants by using an in vitro assay system which is mainly composed of recombinant human immunodeficiency virus type 1 integrase and radiolabeled oligonucleotides. From the above screening, the aqueous methanolic extract of the roots of Agastache rugosa exhibited a significant activity. Bioactivity-guided chromatographic fractionation of the methanolic extract resulted in the isolation of rosmarinic acid. The structure of the compound was determined by spectroscopic data and by the comparison with the reported values. The IC50 of the rosmarinic acid was approximately 10 microg/ml against HIV integrase.

Inhibitory constituents against HIV-1 protease from Agastache rugosa

Two diterpenoid compounds, agastanol (1) and agastaquinone (2), were isolated from the roots of Agastache rugosa (Labiatae). Compound 1 and 2 showed significant inhibitory effects against human immunodeficiency virus type 1 (HIV-1) protease activity with IC50 values of 360 and 87 microM, respectively.