Cycloartane-type triterpenoids from the resinous exudates of Commiphora opobalsamum

The Genus Commiphora: An Overview of Its Traditional Uses, Phytochemistry, Pharmacology, and Quality Control

Myrrh is the resinous substance secreted by plants of the genus Commiphora. In traditional Chinese medicine, Ayurvedic medicine, and traditional Arabic medicine, myrrh is regarded as an important medicinal material, widely used in the treatment of trauma, arthritis, hyperlipidemia, and other diseases. This review explores the evolving scientific understanding of the genus Commiphora, covering facets of ethnopharmacology, phytochemistry, pharmacology, artificial cultivation, and quality control. In particular, the chemical constituents and pharmacological research are reviewed. More than 300 types of secondary metabolites have been identified through phytochemical studies of this genus. Guggulsterone is a bioactive steroid isolated mainly from Commiphora mukul. The two isomers, Z- and E-guggulsterone, have shown a wide range of in vitro and in vivo pharmacological effects, including anti-proliferation, antioxidant, anti-inflammatory, and antibacterial. However, the current scientific research on quality control of medicinal materials and identification of original plants is insufficient, which limits the reproducibility and accuracy of biological activity evaluation experiments. Therefore, the establishment of analytical protocols and standardization of extracts is an important step before biological evaluation. At the same time, in order to find more bioactive substances, it is necessary to strengthen the research on the stems, barks, and leaves of this genus. The sources used in this study include PubMed, CNKI, Web of Science, Google Scholar, and other databases, as well as multinational pharmacopoeias, ancient books of traditional medicine, herbal classics, and modern monographs.

Medicinal plant resin natural products: structural diversity and biological activities

Covering: up to the mid of 2023Plants secrete defense resins rich in small-molecule natural products under abiotic and biotic stresses. This comprehensive review encompasses the literature published up to mid-2023 on medicinal plant resin natural products from six main contributor genera, featuring 275 citations that refer to 1115 structurally diverse compounds. The scope of this review extends to include essential information such as the racemic nature of metabolites found in different species of plant resins, source of resins, and revised structures. Additionally, we carefully analyze the reported biological activities of resins, organizing them based on the their structures. The findings offer important insights into the relationship between their structure and activity. Furthermore, this detailed examination can be valuable for researchers and scientists in the field of medicinal plant resin natural products and will promote continued exploration and progress in this area.

An Unprecedented 4,8-Cycloeudesmane, Further New Sesquiterpenoids, a Triterpene, Steroids, and a Lignan from the Resin of Commiphora myrrha and Their Anti-Inflammatory Activity In Vitro

Myrrh has a long tradition in the treatment of inflammatory diseases. However, many of its (active) constituents are still unknown. In the present study, secondary metabolites were isolated from an ethanolic extract by various separation methods (liquid-liquid partition, silica and RP18 flash chromatography, CPC, and preparative HPLC), their structures were elucidated with NMR spectroscopy and mass spectrometry, and the selected compounds were tested for their effect on LPS-induced NO production by RAW 264.7 murine macrophages. Among the isolated substances are 17 sesquiterpenes (1-17) including the first 4,8-cycloeudesmane (1), a triterpene (38), two phytosterols (39, 40) and one lignan (43), which were previously unknown as natural products. Numerous compounds are described for the first time for the genus Commiphora. Eight of the eleven compounds tested (1, 29, 31, 32, 34-37) showed a statistically significant, concentration-dependent weak to moderate anti-inflammatory effect on NO production in the LPS-stimulated RAW 264.7 macrophages in vitro. For the reference substance, furanoeudesma-1,3-diene, an IC50 of 46.0 µM was determined. These sesquiterpenes might therefore be part of the multi-target molecular principles behind the efficacy of myrrh in inflammatory diseases.

Terpenoids from Myrrh and Their Cytotoxic Activity against HeLa Cells

The oleo-gum resin of Commiphora myrrha (Nees) Engl. has a long history of medicinal use, although many of its constituents are still unknown. In the present investigation, 34 secondary metabolites were isolated from myrrh resin using different chromatographic techniques (silica flash chromatography, CPC, and preparative HPLC) and their structures were elucidated with NMR spectroscopy, HRESIMS, CD spectroscopy, and ECD calculations. Among the isolated substances are seven sesquiterpenes (1-7), one disesquiterpene (8), and two triterpenes (23, 24), which were hitherto unknown, and numerous substances are described here for the first time for C. myrrha or the genus Commiphora. Furthermore, the effects of selected terpenes on cervix cancer cells (HeLa) were studied in an MTT-based in vitro assay. Three triterpenes were observed to be the most toxic with moderate IC₅₀ values of 60.3 (29), 74.5 (33), and 78.9 µM (26). Due to the different activity of the structurally similar triterpenoids, the impact of different structural elements on the cytotoxic effect could be discussed and linked to the presence of a 1,2,3-trihydroxy substructure in the A ring. The influence on TNF-α dependent expression of the intercellular adhesion molecule 1 (ICAM-1) in human microvascular endothelial cells (HMEC-1) was also tested for 4-6, 9-11, 17, 18, 20, and 27 in vitro, but revealed less than 20% ICAM-1 reduction and, therefore, no significant anti-inflammatory activity.

Commiphora myrrh: a phytochemical and pharmacological update

Medicinal plants have a long track record of use in history, and one of them is Commiphora myrrh which is commonly found in the southern part of Arabia, the northeastern part of Africa, in Somalia, and Kenya. Relevant literatures were accessed via Google Scholar, PubMed, Scopus, and Web of Science to give updated information on the phytochemical constituents and pharmacological action of Commiphora myrrh. It has been used traditionally for treating wounds, mouth ulcers, aches, fractures, stomach disorders, microbial infections, and inflammatory diseases. It is used as an antiseptic, astringent, anthelmintic, carminative, emmenagogue, and as an expectorant. Phytochemical studies have shown that it contains terpenoids (monoterpenoids, sesquiterpenoids, and volatile/essential oil), diterpenoids, triterpenoids, and steroids. Its essential oil has applications in cosmetics, aromatherapy, and perfumery. Research has shown that it exerts various biological activities such as anti-inflammatory, antioxidant, anti-microbial, neuroprotective, anti-diabetic, anti-cancer, analgesic, anti-parasitic, and recently, it was found to work against respiratory infections like COVID-19. With the advancement in drug development, hopefully, its rich phytochemical components can be explored for drug development as an insecticide due to its great anti-parasitic activity. Also, its interactions with drugs can be fully elucidated.This review highlights an updated information on the history, distribution, traditional uses, phytochemical components, pharmacology, and various biological activities of Commiphora myrrh. Graphical summary of the phytochemical and pharmacological update of Commiphora myrrh.

The Role of Myrrh Metabolites in Cancer, Inflammation, and Wound Healing: Prospects for a Multi-Targeted Drug Therapy

Background: Myrrh extract is a well-known medicinal plant with significant therapeutic benefits attributed to the activity of its diverse metabolites. It has promising activity against cancer and inflammatory diseases, and could serve as a potential therapeutic alternative since most therapeutic agents have severe side effects that impair quality of life. Method: The current study identified the active metabolites from the myrrh resin methanolic extract. Then, the extracts were tested for in vitro anti-inflammatory and anti-cancer activity using cancer cell lines and Tamm-Horsfall Protein 1 (Thp-1)-like macrophage cell lines. Furthermore, using an in vivo rat model, the extracts’ anti-inflammatory and wound-healing activity was investigated. In addition, in silico predictions of the myrrh constituents highlighted the pharmacokinetic properties, molecular targets, and safety profile, including cytochrome P 450 (CYP) inhibition and organ toxicity. Results: Nine secondary metabolites were identified, and computational predictions suggested a good absorption profile, anticancer, anti-inflammatory, and wound-healing effects. The myrrh extract had moderate cytotoxic activity against both HL60 and K562 leukemia cell lines and the KAIMRC1 breast cancer cell line. Myrrh caused a dose-dependent effect on macrophages to increase the reactive oxygen species (ROS) levels, promote their polarization to classically activated macrophages (M1) and alternatively activated macrophages (M2) phenotypes, and consequently induce apoptosis, highlighting its ability to modulate macrophage function, which could potentially aid in several desired therapeutic processes, including the resolution of inflammation, and autophagy which is an important aspect to consider in cancer treatment. The topical application of myrrh improved wound healing, with no delayed inflammatory response, and promoted complete re-epithelization of the skin, similar to the positive control. In conclusion, we provide evidence for the methanolic extract of myrrh having cytotoxic activity against cancer cells and anti-inflammatory wound-healing properties, which may be attributed to its role in modulating macrophage function. Furthermore, we suggest the active constituents responsible for these properties, which warrants further studies focusing on the precise roles of the active metabolites.

Cycloartane-type triterpenoids from the whole plants of Macrosolen bidoupensis

One new cycloartane-type triterpenoid, named macrobidoupoic acid A (as an C-24 epimeric mixture, 4a, 4 b), together with three known ones (1-3), were clarified by different chromatography from the M. bidoupensis whole plants. Triterpenoids (1, 3 & 4) were detected for the first time from the Macrosolen genus. Chemical structures of them were illuminated using HR-ESI-MS, and NMR (1 D & 2 D) assessments. The cytotoxic properties of triterpenoids (3 & 4) were examined against two human cancer cell lines (A549, and RD) by MTT assay. As results shown, triterpenoids (3 & 4) possessed moderate cytotoxic activity against A549 and RD cancer cells (IC₅₀ ranged from 5.44 to 39.52 μM).

Commikuanoids A-C: New cycloartane triterpenoids with exploration of carbonic anhydrase-II inhibition from the resins of Commiphora kua by in vitro and in silico molecular docking

Three new cycloartane triterpenoids, commikuanoids A-C (1-3), together with four known compounds 4-7, were isolated from the resin of Commiphora kua. Their structures were confirmed by advanced NMR techniques such as 1D (¹H and ¹³C) and 2D (HMBC, HSQC, COSY, NOESY and NOE) and high-resolution mass spectrometry (HRMS). Five compounds (1-5) were screened for in vitro carbonic anhydrase II (CA II) inhibitory activity. All the tested compounds demonstrated significant activity against CA II with IC₅₀ values ranging from 4.9-19.6 μM. Moreover, the binding pattern of each compound in the binding site of CA-II was predicted through in silico molecular docking approach. It was observed that compounds 2, 4, and 5 binds with the Zn ion present in the active site of CA II, while compounds 1 and 3 mediated hydrogen bonding with Thr199 of CA-II, and all the compounds showed good binding score (> - 5 kcal/mol).

Commiphoranes K-O, New Terpenoids from Resina Commiphora and Their Anti-Inflammatory Activities

Commiphorane K (1), a new dinorditerpenoid, commiphoranes L-N (2-4), three new germacrane-type sesquiterpenoids, and commiphorane O (5), one new guaiane-type sesquiterpenoid, were isolated from Resina Commiphora. Their structures were characterized by spectroscopic and computational methods. In particular, the structure of 4 was confirmed by X-ray crystallography. Compounds 2-5 were evaluated for their anti-inflammatory activities. The result shows that compound 2 suppresses lipopolysaccharide (LPS)-stimulated production of TNF-α in RAW264.7 cells in a dose-dependent manner.

The Chemical Structure and Bioactivity of Cycloartane-type Compounds

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For decades now, compounds in the cycloartane-type series have been shown to have versatile pharmacological activities. However, no extensive review has been written to summarize these health-beneficial activities. Therefore, the purpose of this paper is to systematically highlight the biological activities of these compounds, including their antitumor and anti-osteoporosis effects, their effects on receptors, cytokine release, and chronic renal failure, as well as their tyrosinase inhibitory, anticomplement, anti-parasite, anti-HIV, and antituberculosis activities. In this review, we have summarized the structures of over 200 compounds based on their characteristics and described their structureactivity relationships (SARs), and potential mechanisms of action.

Forgotten Perfumery Plants - Part I: Balm of Judea

Perfumes have always been products of great importance, mainly composed of natural, valuable and vegetal raw materials. Today, some of them have completely disappeared in perfumery, even though they are part of our cultural heritage and were commonly used in the past. Balm of Judea is one of the most noble, rare and fascinating ingredient long used in perfumery and medicine, that is missing today. After years of research, we collected a resin and an essential oil (steam distillation of fresh aerial parts) from Commiphora gileadensis (L.) C.Chr. native from Saudi Arabia and cultivated in Israel. The aims of this study were to i) identify the main reasons of the loss of the balm of Judea, ii) characterize the volatile composition of the resin and the essential oil and iii) evaluate their olfactory profile and assess their biological activity. Eighty-three compounds were identified in the resin, by a combination of GC-MS and GC/FID techniques, using direct injection and HS-SPME. α-Pinene (24.0 %), sabinene (43.8 %), β-pinene (6.3 %) and cymene (3.6 %) were the main identified compounds, giving an intense, terpenic and lemony smell to the resin. Anti-inflammatory, wound-healing and whitening activities were highlighted. Sabinene (22.7 %), terpinen-4-ol (18.7 %), α-pinene (14.4 %) and cymene (13.6 %) were identified as the main components of the essential oil, giving a spicy, woody and lemony fragrance. Anti-inflammatory and whitening activities were emphasized.

Seeing the Unseen of the Combination of Two Natural Resins, Frankincense and Myrrh: Changes in Chemical Constituents and Pharmacological Activities

For the treatment of diseases, especially chronic diseases, traditional natural drugs have more effective therapeutic advantages because of their multi-target and multi-channel characteristics. Among many traditional natural medicines, resins frankincense and myrrh have been proven to be effective in the treatment of inflammation and cancer. In the West, frankincense and myrrh have been used as incense in religious and cultural ceremonies since ancient times; in traditional Chinese and Ayurvedic medicine, they are used mainly for the treatment of chronic diseases. The main chemical constituents of frankincense and myrrh are terpenoids and essential oils. Their common pharmacological effects are anti-inflammatory and anticancer. More interestingly, in traditional Chinese medicine, frankincense and myrrh have been combined as drug pairs in the same prescription for thousands of years, and their combination has a better therapeutic effect on diseases than a single drug. After the combination of frankincense and myrrh forms a blend, a series of changes take place in their chemical composition, such as the increase or decrease of the main active ingredients, the disappearance of native chemical components, and the emergence of new chemical components. At the same time, the pharmacological effects of the combination seem magically powerful, such as synergistic anti-inflammation, synergistic anticancer, synergistic analgesic, synergistic antibacterial, synergistic blood-activation, and so on. In this review, we summarize the latest research on the main chemical constituents and pharmacological activities of these two natural resins, along with chemical and pharmacological studies on the combination of the two.

Kleinhospitine E and Cycloartane Triterpenoids from Kleinhovia hospita

A novel cycloartane triterpenoid alkaloid, kleinhospitine E (1), six new cycloartane triterpenoids (2-7), three known cycloartane triterpenoids (8-10), and taraxerone (11) were isolated from a methanol extract of Kleinhovia hospita. Their structures were elucidated by 1D- and 2D-NMR spectroscopy as well as HRMS analysis. The absolute configurations of all isolated compounds were determined from their ECD spectra by comparison with theoretical values. Kleinhospitine E (1) is the first cycloartane alkaloid possessing an unusual γ-lactam with an oxopropylidene side chain. Compounds 2, 3, and 6 were assigned as cycloartane triterpenoids with a 9α,10α-cyclopropyl ring, which is found rarely among naturally occurring compounds, while 4 and 5 were established as isomers of compound 3 containing a 21,23-diacetal side chain. Biological evaluation revealed that compounds 4 and 9 exhibited more potent antiproliferative activities against a multidrug-resistant tumor cell line compared with its parent chemosensitive cell line. Furthermore, compound 6 exhibited submicromolar anti-HIV activity.

Conocarpol, a new cycloartane triterpenoid from Diospyros conocarpa

A new cycloartane triterpenoid named conocarpol (1) was isolated from the stem bark of Diospyros conocarpa, together with the known compounds aridanin (2), lupeol (3), betulin (4), betulinic acid (5), stigmasterol (6), and stigmasterol 3-O-β-d-glucopyranoside (7). Their structures were established on the basis of 1D and 2D NMR spectroscopy as well as mass spectrometry. Aridanin (2) is reported for the first time in the family Ebenaceae, and conocarpol (1) represents the first cycloartane triterpene within this family.

Cycloartan-24-ene-1α,2α,3β-triol, a cycloartane-type triterpenoid from the resinous exudates of Commiphora myrrha, induces apoptosis in human prostatic cancer PC-3 cells

Plant-derived antitumor drugs are currently used in chemotherapy. Cycloartane triterpenoids have shown a cytotoxic effect on human prostate cancer cells. The aim of the present study was to isolate a cycloartane triterpenoid from Commiphora myrrha and evaluate its anticancer potential. Cycloartan-24-ene-1α,2α,3β-triol (MY-1) was isolated from Commiphora myrrha, and its structure was determined through 1H and 13C nuclear magnetic resonance spectroscopy. The cytotoxic and apoptotic effects of MY-1 on human prostatic cancer PC-3 cells were estimated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometric analysis and terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) staining assay, and the expression of apoptotic-related proteins were evaluated by western blotting. MY-1 showed cytotoxic activity on PC-3 cells in a concentration-dependent manner with an IC50 value of 9.6 µM at 24 h. MY-1 induced cell cycle arrest and apoptosis. Western blot analysis revealed that MY-1 regulated the expression levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), p53 and caspase-3 in the PC-3 cells. These findings indicate that MY-1 exerts significantly pro-apoptotic activity against human hormone-independent prostatic cancer and support MY-1 as a potential anticancer drug.

Cycloartane triterpenes from the leaves of Neoboutonia macrocalyx L

Neoboutonia macrocalyx is used by people in south western Uganda around Kibale National Park in the treatment of malaria. Phytochemical investigation on the leaves of this plant led to the isolation of nine cycloartane triterpenes (1-9) and one phenanthrene; 7-methoxy-2,8 dimethyl-9,10-dihydrophenantherene-3,6 diol (10) along with three known compounds which included 22-de-O-acetyl-26-deoxyneoboutomellerone (11), mellerin B (12) and 6-hydroxystigmast-4-en-3-one (13). The chemical structures of the compounds were established mainly through a combination of spectroscopic techniques. The isolated compounds were evaluated for antiplasmodial activity against the chloroquine-resistant FcB1/Colombia strain of Plasmodium falciparum and for cytotoxicity against the KB (nasopharyngeal epidermoid carcinoma) and MRC-5 (human diploid embryonic lung) cells. Seven out of 13 compounds exhibited good antiplasmodial activity with IC50 of ⩽5μg/ml with two compounds exhibiting low cytotoxicity and five compounds having significant cytotoxicity.

The genus Commiphora: a review of its traditional uses, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

The resinous exudates of the Commiphora species, known as 'myrrh', are used in traditional Chinese medicine for the treatment of trauma, arthritis, fractures and diseases caused by blood stagnation. Myrrh has also been used in the Ayurvedic medical system because of its therapeutic effects against inflammatory diseases, coronary artery diseases, gynecological disease, obesity, etc.

AIM OF THE REVIEW

Based on a comprehensive review of traditional uses, phytochemistry, pharmacological and toxicological data on the genus Commiphora, opportunities for the future research and development as well as the genus' therapeutic potential are analyzed.

METHODS

Information on the Commiphora species was collected via electronic search (using Pubmed, SciFinder, Scirus, Google Scholar and Web of Science) and a library search for articles published in peer-reviewed journals. Furthermore, information also was obtained from some local books on ethnopharmacology. This paper covers the literature, primarily pharmacological, from 2000 to the end of December 2011.

RESULTS

The resinous exudates from the bark of plants of the genus Commiphora are important indigenous medicines, and have a long medicinal application for arthritis, hyperlipidemia, pain, wounds, fractures, blood stagnation, in Ayurvedic medicine, traditional Chinese medicine and other indigenous medical systems. Phytochemical investigation of this genus has resulted in identification of more than 300 secondary metabolites. The isolated metabolites and crude extract have exhibited a wide of in vitro and in vivo pharmacological effects, including antiproliferative, antioxidant, anti-inflammatory and antimicrobial. The bioactive steroids guggulsterones have attracted most attention for their potent hypolipidemic effect targeting farnesoid X receptor, as well as their potent inhibitory effects on tumor cells and anti-inflammatory efficiency.

CONCLUSIONS

The resins of Commiphora species have emerged as a good source of the traditional medicines for the treatment of inflammation, arthritis, obesity, microbial infection, wound, pain, fractures, tumor and gastrointestinal diseases. The resin of C. mukul in India and that of C. molmol in Egypt have been developed as anti-hyperlipidemia and antischistosomal agents. Pharmacological results have validated the use of this genus in the traditional medicines. Some bioassays are difficult to reproduce because the plant materials used have not been well identified, therefore analytical protocol and standardization of extracts should be established prior to biological evaluation. Stem, bark and leaf of this genus should receive more attention. Expansion of research materials would provide more opportunities for the discovery of new bioactive principles from the genus Commiphora.

Steroids from Commiphora mukul display antiproliferative effect against human prostate cancer PC3 cells via induction of apoptosis

Two new stigmastane-type steroids, stigmasta-5,22E-diene-3β,11α-diol (1) and stigmasta-5,22E-diene-3β,7α,11α-triol (2), together with eight known compounds, were isolated from the resinous exudates of Commiphora mukul. Their structures were established by extensive analysis of their HR-MS, 1D- and 2D-NMR (COSY, HMQC, HMBC and NOESY) spectra. The isolates were evaluated for their antiproliferative activities against four human cancer cell lines. Compound 2 demonstrated inhibitory effects with IC(50) values of 5.21, 9.04, 10.94 and 16.56 μM, respectively, against K562, MCF-7, PC3 and DU145 human cancer cell lines. Further study showed that 2 was able to enforce the PC3 cell cycle arrest in the G2/M phase, and induce the apoptosis of PC3 cells by activation of Bax, caspases 3 and 9, and by inhibition of Bcl-2. It was also found that 1 inhibited proliferation of PC3 cells via G0/G1 phase arrest of the cell cycle.

Cycloartane-type triterpenoids and sesquiterpenoids from the resinous exudates of Commiphora opobalsamum

Cycloartane-type triterpenoids (1-3), seven sesquiterpenoids (7-13), and five previously reported secondary metabolites, including three cycloartane-type triterpenoids (4-6) and two sesquiterpenoids (14 and 15), were isolated from the resinous exudates of Commiphora opobalsamum. Their structures were elucidated by extensive spectroscopic analysis, including UV, IR, NMR, and MS, and comparison with literature data. The structures of 1, 3, and 7 were confirmed by single-crystal X-ray diffraction analysis. The absolute configuration of 1 was interpreted by the incorporation of CHCl(3) (crystallization solvent) in the crystal and that of 10 was determined by the CD exciton chirality method. Compound 12 represents the first example of a 12-norcadinane-type sesquiterpenoid. Furthermore, compounds 1, 3, 7, and 10-14 were evaluated for cytotoxicity against HeLa and HepG2 cell lines.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids including squalene derivatives, protostanes, lanostanes, holostanes, cycloartanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, lupanes, oleananes, friedelanes, ursanes, hopanes, isomalabaricanes and saponins; 574 references are cited.

Secondary Metabolites from the Liverwort Ptilidium pulcherrimum

A new trinortriterpenoid, diospyrolide acetate (1) and a new diphenylmethane derivative, pulcherrimumin (12), together with ten known pentacyclic triterpenoids (2–11) and four aromatic compounds (13–16), were isolated from the liverwort Ptilidium pulcherrimum. Their structures were established on the basis of extensive analysis of NMR data and by chemical methods. The cytotoxicity of compounds 1–16 was evaluated against the PC3, MDA-MB-231, and Hela cells lines. Ursane triterpenoids 8–10 exhibited moderate cytotoxicity against PC3 cells with IC50 values ranging from 10.1 to 39.7 μM.

Chemical constituents of propolis from Myanmar and their preferential cytotoxicity against a human pancreatic cancer cell line

A methanolic extract of propolis obtained in Myanmar was found to inhibit PANC-1 human pancreatic cancer cells preferentially under nutrient-deprived conditions (NDM), with a PC(50) value of 9.3 microg/mL. Bioactivity-guided fractionation of the extract led to the isolation of two new cycloartane-type triterpenes, (22Z,24E)-3-oxocycloart-22,24-dien-26-oic acid (1) and (24E)-3-oxo-27,28-dihydroxycycloart-24-en-26-oic acid (2), together with 13 cycloartanes (3-13) and four known prenylated flavanones (14-17). Among these, compound 1 exhibited the most potent preferential cytotoxicity (PC(50) 4.3 microM) in a concentration- and time-dependent manner. Furthermore, 1 induced apoptosis-like morphological changes of PANC-1 cells within 24 h of treatment.