Benzophenones and biflavonoids from Rheedia edulis.

Two new polyisoprenylated benzophenones, 32-hydroxy-ent-guttiferone M (1) and 6-epi-guttiferone J (2), along with seven known compounds, 6-epi-clusianone (3), guttiferone A (4), xanthochymol (5), guttiferone E (6), isoxanthochymol (7), (+)-volkensiflavone (8), and (+)-morelloflavone (9), were identified from the seeds and rinds of Rheedia edulis. Compounds 1-3 and 5-9 have been isolated and identified from this species for the first time. The structures of the new compounds were elucidated mainly by analysis of their 1D and 2D NMR spectroscopic data, and their absolute configurations were determined by comparison of their experimental optical rotation and electronic circular dichroism measurements with those values predicted by DFT calculations. Compound 1 showed significant antioxidant activity in both DPPH and ABTS free radical scavenging assays, whereas compound 2 was inactive.

Benzophenones and biflavonoids from Garcinia livingstonei fruits.

A series of 13 known compounds, including seven benzophenones [guttiferone A (1), guttiferone K (2), xanthochymol (3), guttiferone E (4), cycloxanthochymol (5), isoxanthochymol (6), and gambogenone (7)], five biflavonoids [amentoflavone (8), 3,8''-biapigenin (9), (+)-volkensiflavone (10), (+)-morelloflavone (11), and (+)-fukugiside (12)], and the xanthone derivative alloathyriol (13), were identified from the fruits of Garcinia livingstonei (Clusiaceae). This is the first time that compounds 2-7, 9, 12, and 13 have been reported in this species. The cytotoxicity of benzophenones 1 and 2 was assessed for their effect on HCT-116, HT-29, and SW-480 human colon cancer cell lines. Both compounds exhibited strong activity against HCT-116 and HT-29 cell lines with IC(50) values between 5 and 10 microM, and somewhat weaker activity with SW-480 cells (IC(50) values ranging from 18 to 25 microM).

Quantitative analysis of antiradical phenolic constituents from fourteen edible Myrtaceae fruits.

Many species of Myrtaceae are cultivated in home gardens throughout the tropics for their edible fruit, and have been used in traditional medicine to treat several inflammatory conditions. Fruit phenolics are important dietary antioxidant and anti-inflammatory constituents. We have investigated the antiradical activity, total phenolic content (TPC), and total anthocyanin content (TAC) of 14 underutilized Myrtaceae fruits, namely Eugenia aggregata, E. brasiliensis, E. luschnathiana, E. reinwardtiana, Myrciaria cauliflora, M. dubia, M. vexator, Syzygium cumini, S. curranii, S. jambos, S. javanicum, S. malaccense, S. samarangense, and S. samarangense var. Taiwan pink. An HPLC-PDA method was developed to quantify the amounts of cyanidin 3-glucoside (1), delphinidin 3-glucoside (2), ellagic acid (3), kaempferol (4), myricetin (5), quercetin (6), quercitrin (7), and rutin (8) present in MeOH extracts of the fruit. TPC ranged from 3.57 to 101 mg/g, TAC ranged from undetectable to 12.1 mg/g, and antiradical activity, measured as DPPH˙ IC(50), ranged from very active (19.4 µg/ml) to inactive (389 µg/ml).

Cytotoxic chalcones and antioxidants from the fruits of a Syzygium samarangense (Wax Jambu).

Bioassay-guided fractionation of the methanolic extracts of the pulp and seeds of the fruits of Syzygium samarangense Merr. & Perry (Blume) led to the identification of four cytotoxic compounds and eight antioxidants on the basis of HPLC-PDA analysis, MS, and various NMR spectroscopic techniques. Three C-methylated chalcones, 2',4'-dihydroxy-3',5'-dimethyl-6'-methoxychalcone (1), 2',4'-dihydroxy-3'-methyl-6'-methoxychalcone (stercurensin, 2), and 2',4'-dihydroxy-6'-methoxychalcone (cardamonin, 3), were isolated and displayed cytotoxic activity (IC(50) = 10, 35, and 35 µM, respectively) against the SW-480 human colon cancer cell line. Also a number of known antioxidants were obtained including six quercetin glycosides: reynoutrin (4), hyperin (5), myricitrin (6), quercitrin (7), quercetin (9), and guaijaverin (10), one flavanone: (S)-pinocembrin (8), and two phenolic acids: gallic acid (11) and ellagic acid (12).

Bioactive depsides and anthocyanins from jaboticaba (Myrciaria cauliflora).

A new depside, jaboticabin (1), together with 17 known compounds were isolated from the fruit of jaboticaba (Myrciaria cauliflora). The structure of 1 was elucidated by spectroscopic data interpretation. Known compounds were identified by comparison of their spectroscopic data with literature values or by comparison to authentic standards. Compound 1 and the related depside 2-O-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxyphenylacetic acid (2) significantly inhibited chemokine interleukin (IL)-8 production before and after cigarette smoke treatment of cells. Compound 1 was cytotoxic in the HT29 colon cancer cell line (IC50 = 65 microM), and 2 was active against HCT116 colon cancer cells (IC50 = 30 microM). Compounds 1 and 2 also exhibited antiradical activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC50 = 51.4 and 61.8 microM, respectively). Two anthocyanins, cyanidin 3-glucoside (3) and delphinidin 3-glucoside (4), also showed good activity in these assays.

Comparative analyses of bioactive Mammea coumarins from seven parts of Mammea americana by HPLC-PDA with LC-MS.

Mammea americana L. is tropical plant in the Clusiaceae family that bears edible fruit. Mammea coumarins are isoprenylated derivatives of the lactones of the 2-hydroxy-Z-cinnamic acids that are bioactive and have limited distribution in three Clusiaceae genera. Qualitative and quantitative analyses were performed to determine the distribution of mammea coumarins in the seed nucleus, seed coat, fruit flesh, fruit skin, leaf, stem, and root of M. americana using high-performance liquid chromatography-photodiode array detector (HPLC-PDA) and liquid chromatography-mass spectrometry (LC-MS). Ten major mammea coumarins, mammea E/BD (1), mammea E/BC (2), mammea E/BA (3), mammea E/BB (4), mammea B/BA hydroxycyclo F (5), mammea B/BD (6), mammea B/BC (7), mammea B/BA (8), mammea B/BB (9), and mammea B/BA cyclo F (10), were isolated and identified from the seed nucleus of M. americana and employed as standards. The HPLC-PDA method was validated with respect to sensitivity, linearity, recovery, accuracy, and precision. The total content (w/w %) of the 10 major mammea coumarins in M. americana was determined to be highest in the root (0.75%), followed by the leaf (0.64%), seed nucleus (0.48%), fruit skin (0.11%), stem (0.08%), seed coat (0.02%), and fruit flesh (<0.01%). The leaf and seed nucleus are rich and sustainable natural sources of mammea coumarins. Additionally, the described HPLC-PDA and LC-MS methods are sensitive and accurate and can be applied to the analysis of mammea coumarins in other samples.

Antioxidant and cytotoxic isoprenylated coumarins from Mammea americana.

Antioxidant-guided fractionation of Mammea americana L. seeds resulted in the identification of three new isoprenylated coumarins, mammea B/BA hydroxycyclo F (1), mammea E/BC (2), and mammea E/BD (3). In addition, twelve known isoprenylated coumarins, mammea A/AA (4), mammea A/AA cyclo D (5), mammea A/AA cyclo F (6), mammea A/AC cyclo D (7), mammea A/AD cyclo D (8), mammea B/BA (9), mammea B/BA cyclo F (10), mammea B/BB (11), mammea B/BC (12), mammea B/BD (13), mammea E/BA (14), and mammea E/BB (15), as well as two known flavanols, (+)-catechin (16) and (-)-epicatechin (17) were identified. The fifteen isoprenylated coumarins were screened for their cytotoxicity in the SW-480, HT-29, and HCT-116 human colon cancer cell lines and antioxidant capacities in the DPPH (1,1-diphenyl-2-picrylhydrazyl) free-radical assay. Compounds 1 - 15 exhibited significant cytotoxic activities in the SW-480, HT-29, and HCT-116 human colon cancer cell lines (IC50 ranges 13.9 - 88.1, 11.2 - 85.3, and 10.7 - 76.7 microM, in the three cell lines, respectively) at concentrations comparable to 5-fluorouracil (IC50 = 53.0, 46.1, and 45.1 microM), a drug frequently used for human colon cancer treatment. Compounds 2 - 4, 9, and 11 - 15 displayed high antioxidant activity in the DPPH assay (IC50 range 86 - 135 microM), compounds 1, 5 - 8, and 10, however, had no antioxidant activity (IC50 > 200 microg/mL) in the DPPH assay. The results of these assays were used to study the structure-activity relationships for this class of compounds. In the SW-480 cell line, the three new coumarins, 1 - 3, also exhibited dose-dependent increases in sub-diploid cells by flow cytometry, indicating that they induce apoptosis.

Bioactive benzophenones from Garcinia xanthochymus fruits.

A MeOH extract of Garcinia xanthochymus fruits was subjected to activity-guided fractionation, yielding two new benzophenones, guttiferone H (1) and gambogenone (2). Compound 1 contains a seven-membered ring attached to the bicyclo[3.3.1]nonane system at positions 7 and 8 and displayed cytotoxicity in the SW-480 colon cancer cell line (IC(50) = 12 microM). Compound 2 has a novel benzophenone bicyclo[3.3.2]decane system and displayed cytotoxicity in the SW-480 colon cancer cell line (IC(50) = 188 microM). Both 1 and 2 induced apoptosis in SW-480 colon cancer cells and displayed antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC(50) = 64 and 38.7 microM, respectively). The structures of 1 and 2 were established by 1D and 2D NMR data analysis. Eleven known compounds, aristophenone A, alloathyriol, amentoflavone, 3,8' '-biapigenin, cycloxanthochymol, (+/-)-fukugetin, (+/-)-fukugiside, guttiferone E, isoxanthochymol, (+/-)-volkensiflavone, and xanthochymol, were also obtained. The 11 known compounds were also tested against SW-480 colon cancer cells and in the DPPH assay.

Analysis of polyphenolic antioxidants from the fruits of three pouteria species by selected ion monitoring liquid chromatography-mass spectrometry.

Pouteria campechiana, Pouteria sapota, and Pouteria viridis are tropical plants in the Sapotaceae family that bear edible fruits. The fresh fruits of these three Pouteria species were each extracted, and activity-guided fractionations were performed to identify the antioxidant constituents. Seven polyphenolic antioxidants, gallic acid (1), (+)-gallocatechin (2), (+)-catechin (3), (-)-epicatechin (4), dihydromyricetin (5), (+)-catechin-3-O-gallate (6), and myricitrin (7), were isolated and identified. Extracts of the three Pouteria fruits were analyzed by a selected ion monitoring liquid chromatography-mass spectrometry method to quantify their polyphenolic antioxidants. The highest level of the seven measured polyphenols was found in P. sapota, the second highest in P. viridis, and the lowest in P. campechiana. The levels of the seven polyphenols corresponded with the results of the 1,1-diphenyl-2-picrylhydrazyl assay, by which P. sapota had the highest antioxidant activity, P. viridis the second highest, and P. campechiana the lowest.

Bioactive novel polyphenols from the fruit of Manilkara zapota (Sapodilla).

Activity-guided fractionation of a methanol extract from the fruit of Manilkara zapota cv. Tikal resulted in the isolation of two new antioxidants, methyl 4-O-galloylchlorogenate (1) and 4-O-galloylchlorogenic acid (2), along with eight known polyphenolic antioxidants, namely, methyl chlorogenate (3), dihydromyricetin (4), quercitrin (5), myricitrin (6), (+)-catechin (7), (-)-epicatechin (8), (+)-gallocatechin (9), and gallic acid (10). Of the 10 polyphenols, 1 showed the highest antioxidant activity (IC(50) = 12.9 microM) in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assay and displayed cytotoxicity in the HCT-116 and SW-480 human colon cancer cell lines with IC(50) values of 190 and 160 microM, respectively. Compound 2 showed high antioxidant activity (IC(50) = 23.5 microM) in the DPPH free-radical assay and displayed cytotoxicity in the HCT-116 and SW-480 human colon cancer cell lines with IC(50) values of 154 and 134 microM, respectively.

Polyphenolic antioxidants from the fruits of Chrysophyllum cainito L. (Star Apple).

Chrysophyllum cainito L. (Sapotaceae), known commonly as star apple or caimito, is a tropical tree that bears edible fruits. The fruits are grown commercially in certain tropical and subtropical areas, such as southern Florida. In this study, the fresh fruits were extracted with methanol and partitioned with hexane and ethyl acetate sequentially. The ethyl acetate soluble fraction displayed high antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC50 = 22 microg/mL). Activity-guided fractionation of the ethyl acetate soluble fraction was performed to identify the antioxidant constituents. Nine known polyphenolic antioxidants, (+)-catechin (1), (-)-epicatechin (2), (+)-gallocatechin (3), (-)-epigallocatechin (4), quercetin (5), quercitrin (6), isoquercitrin (7), myricitrin (8), and gallic acid, have been identified from the fruits. Of these nine antioxidants, 2 is present in the highest concentration in star apple fruits (7.3 mg/kg fresh weight), and 5 showed the highest antioxidant activity (IC50 = 40 microM) in the DPPH assay.