The Cosmetic Potential of The Medicinal Halophyte Tamarix Gallica L. (Tamaricaceae) Growing in The Eastern Part of Algeria: Photoprotective and Antioxidant Activities.

AIM AND OBJECTIVE: Currently, the use of ingredients from natural sources has gained great attention in the cosmetic field, especially for the development of new photoprotective formulations. Therefore, the present study aimed to evaluate the cosmetic potential of the crude methanol extract and the ethyl acetate fraction of the medicinal halophyte Tamarix gallica L. (Tg) growing in the area of Tebessa in the eastern part of Algeria, by assessing their phenolic and flavonoid contents, photoprotective and antioxidant activities. METHODS: The research approach consisted of determining phenolic and flavonoid contents of aerial parts via Folin-Ciocalteu and aluminum chloride methods, respectively. The antioxidant activity was measured through two in vitro methods, DPPH radical scavenging activity and total antioxidant capacity test (TAC). The in vitro photoprotective effect was evaluated according to the parameter SPF (Sun Protection Factor) by using the UV spectroscopic method in the UV-B region (290-320 nm). RESULTS: The methanol extract (Tg-MeOH) and ethyl acetate (Tg-EtOAc) fraction showed good antioxidant activity with IC50 values of 14.05±0.66, 27.58±1.98 µg/mL respectively in the DPPH test. Furthermore, both extracts displayed strong total antioxidant capacity (287.01±7.85, 246.7±1.12 mg AAE/g, respectively) in the TAC test. Both extracts exhibited high photoprotective activity, with sun protection factor (SPF) values 37.03±0.22 and 36.08±0.03. The antioxidant and photoprotective activities of these extracts were probably related to polyphenols content (190.27±0.74 mg AGE /g and 121.77±1.29 mg AGE /g, respectively) and flavonoids (78.75±0.06 mg QE /g and 58.67±1.19mg/g). CONCLUSION: Our findings show that extracts of Tamarix gallica L. could be a promising source to be mixed as a natural sunscreen and antioxidant agents into photoprotective cosmetic formulations.

Photodynamic action of Hypericum perforatum hydrophilic extract against Staphylococcus aureus.

Hypericin (Hyp) is one of the most effective, naturally occurring photodynamic agents, which proved effective against a wide array of microorganisms. One limitation of its large scale application as a disinfectant is the high production cost of the pure compound. The availability of photoactive materials at a lower cost may be highly beneficial to the actual implementation of photodisinfection also at the industrial level. In this work we report the use of a lyophilized extract from Hypericum perforatum as a photosensitizing material. We show that optical absorption in the green-red region of the visible spectrum of ethanol or DMSO solutions of the lyophilized extract contains bands arising from Hyp. When excited with light in the main Hyp absorption bands, fluorescence emission and triplet state formation occur as in pure Hyp solutions. We show that ethanol or DMSO solutions of the lyophilized extract from Hypericum perforatum are highly efficient photodynamic agents against Gram-positive Staphylococcus aureus, chosen as a model. The performance is indistinguishable from that of the pure compound. Using fluorescence microscopy, we demonstrate that upon incubation of S. aureus with lyophilized extract solutions, Hyp is found on the bacterial wall, as previously reported for the pure compound.

Datura suaveolens and Verbena tenuisecta mediated silver nanoparticles, their photodynamic cytotoxic and antimicrobial evaluation.

Biogenic production of nanoparticles is eco-friendly, less expensive method with various medical and biological applications. Nanotechnology along with photodynamic therapy is gaining tremendous importance with enhanced efficacy. The present work was aimed to evaluate methanolic extracts and nanoparticles of two selected plants (Datura suavolens and Verbina tenuisecta) for cytotoxic photodynamic, antioxidant and antimicrobial study. Both extract and silver (5 mM) nanoparticles of Datura plant showed significant activities against bacterial strains. Maximum ZOI of 27.3 ± 1.6 mm was observed with nanoparticles of Datura branches with minimum inhibitory (MIC) value of 32 µg/ml. In case of antifungal and antioxidant assay samples were moderately active. Silver nanoparticles and extracts were effective against rhabdomyosarcoma cell line with lowest IC50 value of 42.5 ± 0.6 µg/ml and percent viability of 25.6 ± 1.3 of Verbena tenuisecta. However, nanoparticles of Datura leaves and branches were more potent with IC50 value of 2.4 ± 0.9 µg/ml and 7.8 ± 1.1 µg/ml respectively. The result of photodynamic study showed that efficacy of photosensitizer was enhanced and percent viability reduced when nanoparticles used as an adjunct. The color change and UV spectra (415‒425 nm) indicated the production of nanoparticles. Fourier transform infrared spectroscopy (FTIR) spectra showed presence of different functional groups e.g., hydroxyl, carbonyl and amino. Nanoparticles are sphenoid in morphology and size ranges between 20-150 nm. Current study showed these silver nanoparticles can be used as cytotoxic agent in photodynamic therapy and can play a critical role to establish medicinal potential of selected plants.

Protoberberine compounds extracted from Chelidonium majus L. as novel natural photosensitizers for cancer therapy.

BACKGROUND: It has been shown that secondary metabolites occur in Chelidonium majus L. (C. majus) crude extract and milky sap (alkaloids such as berberine, coptisine, chelidonine, chelerythrine, sanguinarine, and protopine) are biologically active compounds with a wide spectrum of pharmacological functions. Berberine, an isoquinoline alkaloid extracted from plants, possesses a wide range of biological activities, including inhibition of growth of a variety of cancer cell lines. PURPOSE AND STUDY DESIGN: In the present study, we investigated the potential anticancer effect of a protoberberine alkaloidal fraction (BBR-F) isolated from the medicinal plant C. majus on HeLa and C33A cervical cancer cells after light irradiation (PDT treatment). METHODS: BBR-F was prepared from an ethanolic extract of stems of C. majus. Identification of alkaloidal compounds was performed using high-performance liquid chromatography - mass spectrometry (HPLC/ESI-MS) and nuclear magnetic resonance (NMR) spectroscopy. BBR-F was then biologically evaluated for its anticancer properties. Cytotoxic activity after PDT treatment and without light irradiation (dark cytotoxicity) was determined by colorimetric WST-1 assay. The impact of the protoberberine alkaloidal fraction on the morphology and function of the cells was assessed by fluorescence and confocal microscopy as well as by flow cytometric analysis. To investigate the proinflammatory effect of the extracted natural BBR-F, nitric oxide concentration was determined using the Griess method. RESULTS: An effective reduction in HeLa and C33A cell viability was observed after PDT treatment of BBR-F treated cells. Furthermore, microscopic analysis identified various morphological changes in the studied cells that occurred during apoptosis. Apoptosis of HeLa and C33A cells was also characterized by biochemical changes in cell membrane composition, activation of intracellular caspases, disruption of the mitochondrial membrane potential (Δψm) and reactive oxygen species (ROS) generation. CONCLUSION: Our results strongly suggest that the components of the natural plant protoberberine fraction (BBR-F) extracted from C. majus may represent promising novel photosensitive agents and can be applied in cancer photodynamic therapy as natural photosensitizers.

Photodynamic therapy with Bixa orellana extract and LED for the reduction of halitosis: study protocol for a randomized, microbiological and clinical trial.

BACKGROUND: Halitosis is an unpleasant breath odour that can interfere with the professional life, social life and quality of life of people who suffer from it. A modality of treatment that has been increasing in dentistry is antimicrobial photodynamic therapy (aPDT). Bixa orellana, popularly known as "urucum" is a plant native to Brazil. The seeds are used to produce a dye that is largely used in the food, textile, paint and cosmetic industries. The aim of this study is to verify whether aPDT with Bixa orellana extract and blue light-emitting diodes (LEDs) is effective in reducing halitosis. This method will also be compared with tongue scraping, the most commonly used conventional method for tongue coating removal, and the association of both methods will be evaluated. METHODS/DESIGN: A randomized clinical trial will be conducted at the dental clinic of the Universidade Nove de Julho. Thirty-nine patients will be divided by block randomization into three groups (n = 13) according to the treatment to be performed. In Group 1, tongue scraping will be performed by the same operator in all patients for analysis of the immediate results. Patients will also be instructed on how to use the scraper at home. Group 2 will be treated with aPDT with Bixa orellana extract and the LED light curing device: Valo Cordless Ultradent®. Six points in the tongue dorsum with a distance of 1 cm between them will be irradiated. The apparatus will be pre-calibrated at wavelength 395-480 nm for 20 s and 9.6 J per point. In Group 3, patients will be submitted to the tongue scraping procedure, as well as to the previously explained aPDT. Oral air collection with the Oral Chroma™ and microbiological collections of the tongue coating shall be done before, immediately after and 7 days after treatment for comparison. DISCUSSION: Halitosis treatment is a topic that still needs attention. The results of this trial could support decision-making by clinicians regarding aPDT using blue LEDs for treating halitosis on a daily basis, as most dentists already have this light source in their offices. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03346460 . Registered on 17 November 2017.

Preclinical Study of Antineoplastic Sinoporphyrin Sodium-PDT via In Vitro and In Vivo Models.

Photodynamic therapy (PDT) investigations have seen stable increases and the development of new photosensitizers is a heated topic. Sinoporphyrin sodium is a new photosensitizer isolated from Photofrin. This article evaluated its anticancer effects by clonogenic assays, MTT assays and xenograft experiments in comparison to Photofrin. The clonogenicity inhibition rates of sinoporphyrin sodium-PDT towards four human cancer cell lines ranged from 85.5% to 94.2% at 0.5 µg/mL under 630 nm irradiation of 30 mW/cm² for 180 s. For MTT assays, the IC50 ranges of Photofrin-PDT and sinoporphyrin sodium-PDT towards human cancer cells were 0.3 µg/mL to 5.5 µg/mL and 0.1 µg/mL to 0.8 µg/mL under the same irradiation conditions, respectively. The IC50 values of Photofrin-PDT and sinoporphyrin sodium-PDT towards human skin cells, HaCaT, were 10 µg/mL and 1.0 µg/mL, respectively. Esophagus carcinoma and hepatoma xenograft models were established to evaluate the in vivo antineoplastic efficacy. A control group, Photofrin-PDT group (20 mg/kg) and sinoporphyrin sodium group at three doses, 0.5 mg/kg, 1 mg/kg and 2 mg/kg, were set. Mice were injected with photosensitizers 24 h before 60 J 630 nm laser irradiation. The tumor weight inhibition ratio of 2 mg/kg sinoporphyrin sodium-PDT reached approximately 90%. Besides, the tumor growths were significantly slowed down by 2 mg/kg sinoporphyrin sodium-PDT, which was equivalent to 20 mg/kg Photofrin-PDT. In sum, sinoporphyrin sodium-PDT showed great anticancer efficacy and with a smaller dose compared with Photofrin. Further investigations are warranted.

Tectona grandis leaf extract, free and associated with nanoemulsions, as a possible photosensitizer of mouse melanoma B16 cell.

Over the past six years we have been studying extracts from tropical, specially Amazon, plants, to search for new sensitizers for photodynamic therapy of cancer and infectious diseases. Tectona grandis is a genus of tropical hardwood trees in the mint family, Lamiaceae. That is native to south and southeast Asia, but since the end of the 20th century is also gaining ground in the Amazon. The present work aims to evaluate the photodynamic potential of hydro-alcoholic extract from Tectona grandis LF leaves (TGE) and the same extract prepared as the oil-water nanoemulsion (TGE-NE) against melanoma B16 F10 cells. The method for preparation of a stable nanoemulsion with ~20nm particles associated to the TGE (TGE-NE) was successfully developed. We have shown that both free and nanostructured presentations possess the ability to sensitize B16 F10 cells to red light of the LED in vitro. Photodynamic effect was observed for both TGE and TGE-NE because toxicity increased under illumination with red light. While TGE was highly toxic towards melanoma cells under illumination with red light of the LED, it also possessed significant dark toxicity towards both B16 F10 and murine fibroblast NIH3T3 cells. The TGE-NE showed reasonable photocytotoxicity and was much less toxic towards normal cells in the dark compared to free TGE.

Targeting T Cell Bioenergetics by Modulating P-Glycoprotein Selectively Depletes Alloreactive T Cells To Prevent Graft-versus-Host Disease.

T lymphocytes play a central role in many human immunologic disorders, including autoimmune and alloimmune diseases. In hematopoietic stem cell transplantation, acute graft-versus-host-disease (GVHD) is caused by an attack on the recipient's tissues from donor allogeneic T cells. Selectively depleting GVHD-causing cells prior to transplant may prevent GVHD. In this study, we evaluated 24 chalcogenorhodamine photosensitizers for their ability to selectively deplete reactive T lymphocytes and identified the photosensitizer 2-Se-Cl, which accumulates in stimulated T cells in proportion to oxidative phosphorylation. The photosensitizer is also a potent stimulator of P-glycoprotein (P-gp). Enhanced P-gp activity promotes the efficient removal of photosensitizer not sequestered in mitochondria and protects resting lymphocytes that are essential for antipathogen and antitumor responses. To evaluate the selective depletion of alloimmune responses, donor C57BL/6 splenocytes were cocultured for 5 d with irradiated BALB/c splenocytes and then photodepleted (PD). PD-treated splenocytes were infused into lethally irradiated BALB/c (same-party) or C3H/HeJ (third-party) mice. Same-party mice that received PD-treated splenocytes at the time of transplant lived 100 d without evidence of GVHD. In contrast, all mice that received untreated primed splenocytes and third-party mice that received PD-treated splenocytes died of lethal GVHD. To evaluate the preservation of antiviral immune responses, acute lymphocytic choriomeningitis virus infection was used. After photodepletion, expansion of Ag-specific naive CD8(+) T cells and viral clearance remained fully intact. The high selectivity of this novel photosensitizer may have broad applications and provide alternative treatment options for patients with T lymphocyte-mediated diseases.

Reduction of Candida tropicalis biofilm by photoactivation of a Heterophyllaea pustulata extract.

CONTEXT: Biofilm formation is an important problem, since this growth mode confers resistance to drugs usually used in therapeutics. OBJECTIVE: In vitro antifungal activity of extracts obtained from Heterophyllaea pustulata Hook f. (Rubiaceae) were studied against Candida tropicalis biofilms, evaluating the effect of irradiation and the oxidative and nitrosative stresses as possible mechanisms of action. MATERIALS AND METHODS: Hexane, benzene, ethyl acetate and ethanol extracts were evaluated at three concentrations (0.2, 0.1 and 0.05 mg/mL) over mature biofilm, under darkness and irradiation. After 48 h of incubation, biofilm quantitation was performed by the O'Toole and Kolter method. Reactive oxygen species (ROS) was measured by nitro-blue tetrazolium (NBT) reaction and reactive nitrogen intermediates (RNI) by the Griess reagent. Superoxide dismutase activation (SOD, NBT assay) and total antioxidant system (FRAP test) were studied. RESULTS: Only the benzene extract at 0.2 mg/mL reduced the biofilms formation. The slight decrease achieved in darkness (17.06 ± 2.80% reduction) was increased by light action (39.31 ± 3.50% reduction), clearly observing a photostimulation. This great reduction was confirmed by confocal microscopy. In darkness, biofilm reduction was mediated by an increase in RNI, whereas under irradiation, the ROS action was most important. Although no SOD activation was observed, a strong stimulation of the total antioxidant system was detected. HPLC analysis established a high content of several anthraquinones in this extract. DISCUSSION AND CONCLUSION: Biofilm reduction by benzene extract was mainly mediated by oxidative stress triggered under light action, confirming a photodynamic sensitization, which could be attributed to its high content of photosensitizing anthraquinones.

Methods for the detection of reactive oxygen species employed in the identification of plant photosensitizers.

Over the past ten years, alternative methods for the rapid screening of PSs have been developed. In the present work, a study was undertaken to correlate the phototoxicity of plant extracts on either prokaryotic or eukaryotic cells, with the total oxidation status (TOS) as well as with their ability to produce 1O2. Results demonstrated that the extracts containing PSs that were active either on eukaryotic cells or bacteria increased their TOS after illumination, and that there was a certain degree of positive correlation between the extract phototoxic efficacy and TOS levels. The production of 1O2 by the illuminated extracts was indirectly measured by the use of the fluorescence of "singlet oxygen sensor green", which is a method that has proved highly sensitive for such measurement. 1O2 was detectable only upon illumination of the most active extracts. In addition, the oxidation of tryptophan and was employed as a method capable of measuring ROS generated by both type I and II ROS reactions. However, it turned out to be not sensitive enough to detect the species generated by plant extracts. Results demonstrated that the TOS method, initially developed to measure the oxidant status in plasma, can be readily applied to plant extracts. Unlike the method used to detect 1O2, the method employed for the detection of TOS proved to be accurate, since all the extracts that displayed a high phototoxic activity on either prokaryotic or eukaryotic cells, presented high TOS levels after illumination.

Visible light absorption and photo-sensitizing properties of spinach leaves and beetroot extracted natural dyes.

Herein, chlorophyll and betalain dyes are extracted from fresh spinach leaves and beetroots. Fourier transform infrared spectra are used to identify the characteristic peaks of the extracted dyes. UV-vis light absorption characteristics of the dyes and their mixed counterpart are investigated by varying their pH and temperature. These dyes are used as photo sensitizer for fabrication of zinc oxide photo-anode based dye sensitized solar cells (DSSCs). The photo-voltaic characteristics of the developed DSSCs are measured under simulated solar light (power of incident light 100 mW cm(-2) from Air Mass 1.5G). The solar to electric conversion efficiencies for the chlorophyll, betalain and mixed dye based solar cells are estimated as 0.148%, 0.197% and 0.294% respectively. The highest conversion efficiency for mixed dye based solar cell is attributed due to the absorption of wider range of solar spectrum.

Prioritization of natural extracts by LC-MS-PCA for the identification of new photosensitizers for photodynamic therapy.

Photodynamic therapy (PDT) is an alternative treatment for cancer that involves administration of a photosensitive drug or photosensitizer that localizes at the tumor tissue followed by in situ excitation at an appropriate wavelength of light. Tumour tissues are then killed by cytotoxic reactive oxygen species generated by the photosensitizer. Targeted excitation and photokilling of affected tissues is achieved through focal light irradiation, thereby minimizing systemic side effects to the normal healthy tissues. Currently, there are only a small number of photosensitizers that are in the clinic and many of these share the same structural core based on cyclic tetrapyrroles. This paper describes how metabolic tools are utilized to prioritize natural extracts to search for structurally new photosensitizers from Malaysian biodiversity. As proof of concept, we analyzed 278 photocytotoxic extracts using a hyphenated technique of liquid chromatography-mass spectrometry coupled with principal component analysis (LC-MS-PCA) and prioritized 27 extracts that potentially contained new photosensitizers for chemical dereplication using an in-house UPLC-PDA-MS-Photocytotoxic assay platform. This led to the identification of 2 new photosensitizers with cyclic tetrapyrrolic structures, thereby demonstrating the feasibility of the metabolic approach.

Isolation, analysis and structures of phototoxic fagopyrins from buckwheat.

Buckwheat products are commonly used in health foods and food supplements. However, public awareness regarding the presence of photodynamic naphthodianthrones fagopyrins that can cause photosensitization is low. At least two additional compounds with structures similar to that of fagopyrin are known to exist; however, the structures of these compounds have never been determined. In this work, we improved the extraction procedure and the chromatographic analysis of fagopyrins by developing a simple, sensitive and high-resolution high performance liquid chromatography (HPLC) analytical method using fluorescence detection. We observed at least six fagopyrin derivatives, which were isolated and characterized via UV-Vis absorption, NMR spectroscopy and mass spectrometry. We determined the structures of two new derivatives (fagopyrin A and fagopyrin E) and proved the existence of protofagopyrins that can transform into fagopyrins upon light exposure. Our methods complement the existing knowledge regarding fagopyrins and will allow for their further analysis, isolation and investigation of their biological activity.

Rapid identification of cyclic tetrapyrrolic photosensitisers for photodynamic therapy using on-line hyphenated LC-PDA-MS coupled with photo-cytotoxicity assay.

INTRODUCTION: Photodynamic therapy is a treatment modality that involves site-directed generation of cytotoxic reactive oxygen species by light-activated photosensitisers. OBJECTIVE: In order to rapidly identify new photosensitisers from natural extracts, we developed a liquid chromatography-photodiode array-mass spectrometry (LC-PDA-MS) method to rapidly identify plant extracts that contain photosensitisers, particularly those possessing a cyclic tetrapyrrole structure. METHOD: Six previously isolated compounds (1-6) were identified in bioactive fractions derived from 15 plant extracts on the basis of their chromatographic retention times, UV-visible profiles, accurate mass and fragmentation patterns. RESULTS: Samples containing uncommon photosensitisers were rapidly identified using this method, and subsequent scale-up isolation efforts led to two new compounds (7 and 8) which were confirmed to be active photosensitisers in a photo-cytotoxicity assay. CONCLUSION: This method serves as a useful tool in prioritising samples that may contain new photosensitisers out of a larger group of photo-cytotoxic natural products extracts.

Derivatives of pheophorbide-a and pheophorbide-b from photocytotoxic Piper penangense extract.

In our screening program for new photosensitizers from Malaysian biodiversity for photodynamic therapy (PDT) of cancer, MeOH extracts of ten terrestrial plants from Cameron Highlands in Pahang, Peninsular Malaysia, were tested. In a short-term 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, 20 µg/ml each of these extracts were incubated in a pro-myelocytic leukemia cell-line, HL60, with or without irradiation with 9.6 J/cm(2) of a broad spectrum light. Three samples, Labisia longistyla, Dichroa febrifuga, and Piper penangense, were photocytotoxic by having at least twofold lower cell viability when irradiated compared to the unirradiated assay. The extract of the leaves of Piper penangense, a shrub belonging to the family Piperaceae and widely distributed in the tropical and subtropical regions in the world, was subsequently subjected to bioassay-guided fractionation using standard chromatography methods. Eight derivatives of pheophorbide-a and -b were identified from the fractions that exhibited strong photocytotoxicity. By spectroscopic analysis, these compounds were identified as pheophorbide-a methyl ester (1), (R,S)-13(2) -hydroxypheophorbide-a methyl ester (2 and 3), pheophorbide-b methyl ester (4), 13(2) -hydroxypheophorbide-b methyl ester (5), 15(2) -hydroxylactone pheophorbide-a methyl ester (6), 15(2) -methoxylactone pheophorbide-a methyl ester (7), 15(2) -methoxylactone pheophorbide-b methyl ester (8).

Systematic analysis of in vitro photo-cytotoxic activity in extracts from terrestrial plants in Peninsula Malaysia for photodynamic therapy.

One hundred and fifty-five extracts from 93 terrestrial species of plants in Peninsula Malaysia were screened for in vitro photo-cytotoxic activity by means of a cell viability test using a human leukaemia cell-line HL60. These plants which can be classified into 43 plant families are diverse in their type of vegetation and their natural habitat in the wild, and may therefore harbour equally diverse metabolites with potential pharmaceutical properties. Of these, 29 plants, namely three from each of the Clusiaceae, Leguminosae, Rutaceae and Verbenaceae families, two from the Piperaceae family and the remaining 15 are from Acanthaceae, Apocynaceae, Bignoniaceae, Celastraceae, Chrysobalanaceae, Irvingiaceae, Lauraceae, Lythraceae, Malvaceae, Meliaceae, Moraceae, Myristicaceae, Myrsinaceae, Olacaceae and Sapindaceae. Hibiscus cannabinus (Malvaceae), Ficus deltoidea (Moraceae), Maranthes corymbosa (Chrysobalanaceae), Micromelum sp., Micromelum minutum and Citrus hystrix (Rutaceae), Cryptocarya griffithiana (Lauraceae), Litchi chinensis (Sapindaceae), Scorodocarpus bornensis (Olacaceae), Kokoona reflexa (Celastraceae), Irvingia malayana (Irvingiaceae), Knema curtisii (Myristicaceae), Dysoxylum sericeum (Meliaceae), Garcinia atroviridis, Garcinia mangostana and Calophyllum inophyllum (Clusiaceae), Ervatamia hirta (Apocynaceae), Cassia alata, Entada phaseoloides and Leucaena leucocephala (Leguminosae), Oroxylum indicum (Bignoniaceae), Peronema canescens,Vitex pubescens and Premna odorata (Verbenaceae), Piper mucronatum and Piper sp. (Piperaceae), Ardisia crenata (Myrsinaceae), Lawsonia inermis (Lythraceae), Strobilanthes sp. (Acanthaceae) were able to reduce the in vitro cell viability by more than 50% when exposed to 9.6J/cm(2) of a broad spectrum light when tested at a concentration of 20 microg/mL. Six of these active extracts were further fractionated and bio-assayed to yield four photosensitisers, all of which are based on the pheophorbide-a and -b core structures. Our results suggest that the main photosensitisers from terrestrial plants are likely based on the cyclic tetrapyrrole structure and photosensitisers with other structures, if present, are present in minor amounts or are not as active as those with the cyclic tetrapyrrole structure.

Photocytotoxic pheophorbide-related compounds from Aglaonema simplex.

In our screening program for new photosensitizers from the Malaysian biodiversity, we found five pheophorbide-related compounds from the leaves and stems of Aglaonema simplex. Detailed spectroscopic analyses showed that compounds 1-3 and 5 are pheophorbide and hydroxy pheophorbide derivatives of chlorophyll a and b. Compound 4, identified as 15(1)-hydroxypurpurin-7-lactone ethyl methyl diester, was isolated for the first time from the Araceae family. An MTT-based short-term survival assay showed that all five compounds exhibit moderate-to-strong photocytotoxic activities towards human leukemia (HL60) and two oral squamous carcinoma cell lines (HSC-2 and HSC-3). Compounds 4 and 5 showed the strongest photocytotoxicities, with IC(50) values of 0.30-0.41 muM (Table 2). Compounds 1-3 with Et chains at C(17(3)) were less photocytotoxic than the parent pheophorbide a (5).

A novel porphyrin photosensitizer from bamboo leaves that induces apoptosis in cancer cell lines.

BACKGROUND: In the screening of new anticancer agents, we found that a methanol extract of bamboo leaves induced rapid apoptosis in the human leukemia CMK-7 cell line. MATERIALS AND METHODS: The active compounds in the extract were isolated by chromatographic methods and their structures were determined by NMR and mass spectroscopy. Apoptosis by the compounds were evaluated in CMK-7 and human colon adenocarcinoma Colo320 DM cells by monitoring the caspase-3 activation and DNA cleavage. RESULTS: The active compounds are 201-hydroxypurpurin-7 delta-lactone ethyl methyl diester (1) and the corresponding methyl phytyl diester (2). The apoptosis by compound 1 (0.3 to 0.1 microM for CMK-7 cells) was enhanced when the culture was briefly irradiated with a fluorescent lamp. This photodynamic induction of apoptosis by compound 1 was much stronger than that by a known photosensitizer, pyropheophorbidemethyl. Compound 2 was a weaker inducer of apoptosis than compound 1, but the apoptosis occurred after light irradiation. CONCLUSION: The 201-hydroxypurpurin-7 delta-lactone esters are promising lead compounds as photosensitizers for photodynamic therapy of cancer.

1,5-dihydroxyanthraquinones and an anthrone from roots of Rumex crispus.

From the roots of Rumex crispus, two known anthraquinones and a new one together with a new anthrone were isolated and the structures of compounds 1-4 were elucidated by spectroscopic means. The singlet oxygen generation capacity was tested with 1,3-diphenylisobenzofuran (DPBF) for compounds 1-4.

Photosensitization and mutation induced in Escherichia coli and Saccharomyces cerevisiae strains by dorstenin, a psoralen analog isolated from Dorstenia bahiensis.

Dorstenin, 5-[3-(4,5-dihydro-5,5-dimethyl-4-oxo-2-furanyl)-butoxy]-7H-furo[3, 2-g] benzopyran-7-one, is a psoralen analog recently isolated from Dorstenia species (Moraceae). In order to characterize its biological activity, its photosensitizing and mutational properties were measured in wild-type E. coli and S. cerevisiae and also in strains carrying mutations which affect DNA repair. Compared to the high activities of psoralen and bergapten, dorstenin showed lower genotoxic effect.