Triple negative human breast cancer (TNBC) is an aggressive cancer subtype with poor prognosis. Besides the better-known artemisinin, Artemisia annua L. contains numerous active compounds not well-studied yet. High-performance liquid chromatography coupled with diode-array and mass spectrometric detection (HPLC-DAD-MS) was used for the analysis of the most abundant compounds of an Artemisia annua extract exhibiting toxicity to MDA-MB-231 TNBC cells. Artemisinin, 6,7-dimethoxycoumarin, arteannuic acid were not toxic to any of the cancer cell lines tested. The flavonols chrysosplenol d and casticin selectively inhibited the viability of the TNBC cell lines, MDA-MB-231, CAL-51, CAL-148, as well as MCF7, A549, MIA PaCa-2, and PC-3. PC-3 prostate cancer cells exhibiting high basal protein kinase B (AKT) and no ERK1/2 activation were relatively resistant, whereas MDA-MB-231 cells with high basal ERK1/2 and low AKT activity were more sensitive to chrysosplenol d treatment. In vivo, chrysosplenol d and casticin inhibited MDA-MB-231 tumor growth on chick chorioallantoic membranes. Both compounds induced mitochondrial membrane potential loss and apoptosis. Chrysosplenol d activated ERK1/2, but not other kinases tested, increased cytosolic reactive oxygen species (ROS) and induced autophagy in MDA-MB-231 cells. Lysosomal aberrations and toxicity could be antagonized by ERK1/2 inhibition. The Artemisia annua flavonols chrysosplenol d and casticin merit exploration as potential anticancer therapeutics.

The target compound 3-amino-1-(2,5-d ichlorophenyl)-8-methoxy-1H-benzo[f]-chromene-2-carbonitrile (4) was synthesized via a reaction of 6-methoxynaphthalen-2-ol (1), 2,5-dichlorobenzaldehyde (2), and malononitrile (3) in ethanolic piperidine solution under microwave irradiation. The newly synthesized β-enaminonitrile was characterized by FT-IR, ¹H NMR, ¹³C NMR, mass spectroscopy, elemental analysis and X-ray diffraction data. Its cytotoxic activity was evaluated against three different human cancer cell lines MDA-MB-231, A549, and MIA PaCa-2 in comparison to the positive controls etoposide and camptothecin employing the XTT cell viability assay. The analysis of the Hirshfeld surface was utilized to visualize the reliability of the crystal package. The obtained results confirmed that the tested molecule revealed promising cytotoxic activities against the three cancer cell lines. Furthermore, theoretical calculations (DFT) were carried out with the Becke3-Lee-Yang-parr (B3LYP) level using 6-311++G(d,p) basis. The optimization geometry for molecular structures was in agreement with the X-ray structure data. The HOMO-LUMO energy gap of the studied system was discussed. The intermolecular-interactions were studied through analysis of the topological-electron-density(r) using the QTAIM and NCI methods. The novel compound exhibited favorable ADMET properties and its molecular modeling analysis showed strong interaction with DNA methyltransferase 1.

Breast cancer is the most common cancer type and a primary cause of cancer mortality among females worldwide. Here, we analyzed the anticancer efficacy of a novel bromochlorinated monoterpene, PPM1, a synthetic analogue of polyhalogenated monoterpenes from Plocamium red algae and structurally similar non-brominated monoterpenes. PPM1, but not the non-brominated monoterpenes, decreased selectively the viability of several triple-negative as well as triple-positive breast cancer cells with different p53 status without significantly affecting normal breast epithelial cells. PPM1 induced accumulation of triple-negative MDA-MB-231 cells with 4N DNA content characterized by decreased histone H3-S10/T3 phosphorylation indicating cell cycle arrest in the G₂ phase. Western immunoblot analysis revealed that PPM1 treatment triggered an initial rapid activation of Aurora kinases A/B/C and p21^Waf1/Cip1 accumulation, which was followed by accumulation of polyploid >4N cells. Flow cytometric analysis showed mitochondrial potential disruption, caspase 3/7 activation, phosphatidylserine externalization, reduction of the amount polyploid cells, and DNA fragmentation consistent with induction of apoptosis. Cell viability was partially restored by the pan-caspase inhibitor Z-VAD-FMK indicating caspase contribution. In vivo, PPM1 inhibited growth, proliferation, and induced apoptosis in MDA-MB-231 xenografted onto the chick chorioallantoic membrane. Hence, Plocamium polyhalogenated monoterpenes and synthetic analogues deserve further exploration as promising anticancer lead compounds.

Photodynamic therapy (PDT) is a non-invasive treatment strategy that includes the combination of three components—a photosensitizer, a light source, and tissue oxygen. PDT can be used for the treatment of skin diseases such as squamous cell carcinoma. The photosensitizer used in this study is the naturally derived chlorophyll derivative chlorin e6 (Ce6), which was encapsulated in ultradeformable ethosomes. Singlet oxygen production by Ce6 upon laser light irradiation was not significantly affected by encapsulation into ethosomes. PDT of squamous cell carcinoma cells treated with Ce6 ethosomes triggered increased mitochondrial superoxide levels and increased caspase 3/7 activity, resulting in concentration- and light-dose-dependent cytotoxicity. Ce6 ethosomes showed good penetration into 3D squamous cell carcinoma spheroids, which upon laser light irradiation exhibited reduced size, proliferation, and viability. The PDT effect of Ce6 ethosomes was specific and showed higher cytotoxicity against squamous cell carcinoma spheroids compared to normal skin fibroblast spheroids. In addition, PDT treatment of squamous cell carcinoma xenografts grown on chorioallantoic membranes of chick eggs (CAM) exhibited reduced expression of Ki-67 proliferation marker and increased terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining, indicating reduced proliferation and activation of apoptosis, respectively. The results demonstrate that Ce6-loaded ethosomes represent a convenient formulation for photodynamic treatment of squamous cell carcinoma.

Oleogum resins of the genus Commiphora have been used in traditional medicines for centuries. More than 200 Commiphora species exhibit highly variable phytochemical compositions. A novel highly selective, sensitive, accurate HPLC-MS/MS method was developed and validated to quantify five characteristic phytosteroids and furanosesquiterpenoids, namely (E)-guggulsterone, (Z)-guggulsterone, curzerenone, furanoeudesma-1,3-diene, and myrrhone. The resulting contents and additionally GC analysis were used to classify and differentiate Commiphora oleogum resins of the species C. myrrha, C. erythraea, C. mukul, C. holtziana, C. confusa, and C. kua, as well as unspecified resins. Interestingly, a Commiphora sample from Ogaden, Ethiopia, comprised 446 ng/mg guggulsterones presumed to be unique to C. mukul from the Indian subcontinent. However, Commiphora from Ogaden differed considerably from C. mukul in respect to guggulsterones isomer’s ratio. Moreover, the cytotoxicity of Commiphora extracts, essential oils, botanical drugs containing Commiphora, and pure compounds against the epidermoid carcinoma A431, malignant melanoma RPMI-7951 and SK-MEL-28 cells was investigated in vitro. Thereby, especially C. mukul extract and C. myrrha essential oil exhibited high cytotoxicity against skin cancer cells with IC₅₀ of 2.9–10.9 µg/mL, but were less toxic to normal keratinocytes. In summary, Commiphora oleogum resins and its phytochemicals warrant further investigation aiming at chemotaxonomical classification as well as application in skin cancer treatment.

Mangosteen (Garcinia mangostana) is well-known for its nutritional value and health benefits. Breast cancer is the most common cancer and the leading cause of cancer-related mortality among females worldwide. Here we show that the prenylated xanthones, α-mangostin, γ-mangostin, 9-hydroxycalabaxanthone (9-HCX), and garcinone E from the mangosteen pericarp exhibit cytotoxicity against a panel of human cancer cell lines including lung adenocarcinoma (A549), cervical carcinoma (HeLa), prostatic carcinoma (DU 145), pancreatic carcinoma (MIA PaCa-2), hepatocellular carcinoma (Hep G2), bladder urothelial cancer (5637), as well as the triple-negative breast cancer cells MDA-MB-231. In line with its higher predicted bioactivity score compared to other prenylated xanthones, 9-HCX induced the strongest antiproliferative and proapoptotic effects in MDA-MB-231 breast cancer xenografts in vivo. In different in vitro models, we demonstrate that prenylated xanthones from G. mangostana target mitochondria in cancer cells by inhibition of the mitochondrial respiratory chain complex II (α-mangostin, γ-mangostin, and garcinone E) and complex III (9-HCX) as shown in isolated mitochondria. Accordingly, oxidative mitochondrial respiration (OXPHOS) was inhibited, mitochondrial proton leak increased, and adenosine triphosphate (ATP) synthesis decreased as analyzed by Seahorse assay in MDA-MB-231 cells. Hence, the prenylated xanthones increased mitochondrial superoxide levels, induced mitochondrial membrane permeabilization, and initiated caspase 3/7-mediated apoptosis in MDA-MB-231 triple-negative breast cancer cells. Thus, prenylated xanthones from Garcinia mangostana exhibit anticancer activity based on interference with the mitochondrial respiration.