Allan Patrick Macabeo | University Of Santo Tomas (original) (raw)
Papers by Allan Patrick Macabeo
Biochemical Systematics and Ecology, 2007
Uvaria rufa Blume is known locally as ''susung kalabaw&... more Uvaria rufa Blume is known locally as ''susung kalabaw'', due to the resemblance of its fruits to the mammary organ of the Philippine carabao. It is a short climbing shrub that grows in low-and medium-altitude thickets of Northern Luzon to Palawan and Mindanao. An alcoholic tincture of its roots is used ethnomedically as ecbolic (Quisumbing, 1978). Fresh leaves were collected in the forest of Mt. Cordillera, Ilocos Sur Province in October 2003. The plant was identified by Asst. Prof. Rosie A. Madulid and a voucher specimen (USTH4897) is ...
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Synlett, 2008
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Philippine Journal of Systematic Biology
The taxonomic classification and unique characteristics of an air-borne actinomycete exhibiting a... more The taxonomic classification and unique characteristics of an air-borne actinomycete exhibiting a dark orange pigmentation were determined by polyphasic analysis. The colony appeared as a contaminant in an agar plate culture of the marine luminous bacterium: Vibrio fischeri USTCMS 1026. Subsequent investigation identified the actinomycete contaminant as MP 1066 for Mycobacterium phlei USTCMS 1066 but was later found to have morphological, physiological, biochemical and genotypic characteristics compatible with member species of the genus Gordonia. BLAST comparison of MP 1066 yielded 100% 16S rDNA sequence alignment with Gordonia terrae so the strain was renamed as Gordonia terrae USTCMS 1066. Its antimicrobial susceptibility profile is similar to that of the pathogenic mycobacteria yielding small MICs and large inhibition zones against the antibiotics: ampicillin (AMP), azithromycin (AZT), amoxicillin-clavulanic acid (AUC), ciprofloxacin (CIP), ethambutol (ETHAM), isoniazid (INH), r...
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Opioids such as morphine, codeine, and oxycodone are extracts or analogs isolated from a single s... more Opioids such as morphine, codeine, and oxycodone are extracts or analogs isolated from a single source: the opium poppy. For a long time, it was believed to be nature’s only source of opioids. But it now appears that biological diversity has evolved an alternative source of opioid compounds—those derived from the plant Mitragyna speciosa. This plant, known as Kratom in Thailand or Biak-Biak in Malaysia, has long been used locally as treatment for pain, fever reduction, diarrhea, and even depression. Kratom and Other Mitragynines: The Chemistry and Pharmacology of Opioids from a Non-Opium Source presents an introduction to the chemical and biological properties of alkaloids isolated from M. speciosa as well as their synthetic analogs. The book covers various topics including phytochemistry, medicinal chemistry, and pharmacology. Current research, analgesic effects, and addiction potential are also discussed. As the first extensive text on the basic science and clinical use of Kratom,...
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Natural product communications, 2012
A synthesis of a new alkaloid-fullerene conjugate (1) is reported. The reaction was carried out b... more A synthesis of a new alkaloid-fullerene conjugate (1) is reported. The reaction was carried out by photoinduced [3+2] cycloaddition of the Alstonia indole alkaloid, 6,7-seco-angustilobine B (2), to fullerene[C60] (3) under aerobic conditions. The major monoaddition photoadduct (1) was characterized unambiguously by UV, IR, MALDI-TOFMS and NMR experiments. A mechanism highlighted by sequential photoinduced electron transfer andradical recombination pathways is also proposed. No significant enhancement in inhibition against M. tuberculosis H37Rv was observed for 1 compared with its parent compounds 2 and 3.
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Philippine Journal of Systematic Biology
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Asian Pacific Journal of Tropical Medicine, 2012
To investigate the inhibitory activity of the chloroform extract, petroleum ether and chloroform ... more To investigate the inhibitory activity of the chloroform extract, petroleum ether and chloroform sub-extracts, lead-acetate treated chloroform extract, fractions and secondary metabolites of Uvaria rufa (U. rufa) against Mycobacterium tuberculosis (M. tuberculosis) H(37)Rv. The antituberculosis susceptibility assay was carried out using the colorimetric Microplate Alamar blue assay (MABA). In addition, the cytotoxicity of the most active fraction was evaluated using the VERO cell toxicity assay. The in vitro inhibitory activity against M. tuberculosis H(37)Rv increased as purification progressed to fractionation (MIC up to 23 μg/mL). The chloroform extract and its sub-extracts showed moderate toxicity while the most active fraction from chloroform sub-extract exhibited no cytotoxicity against VERO cells. Meanwhile, the lead acetate-treated crude chloroform extract and its fractions showed complete inhibitions (100%) with MIC values up to 8 μg/mL. Phytochemical screening of the most active fraction showed, in general, the presence of terpenoids, steroids and phenolic compounds. Evaluation of the antimycobacterial activity of known secondary metabolites isolated showed no promising inhibitory activity against the test organism. The present results demonstrate the potential of U. rufa as a phytomedicinal source of compounds that may exhibit promising antituberculosis activity. In addition, elimination of polar pigments revealed enhanced inhibition against M. tuberculosis H(37)Rv. While several compounds known for this plant did not show antimycobacterial activity, the obtained results are considered sufficient reason for further study to isolate the metabolites from U. rufa responsible for the antitubercular activity.
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Phytochemistry, 2005
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Journal of Ethnopharmacology, 2014
Premna odorata Blanco (Lamiaceae) is a medicinal plant traditionally used in Albay Province, in s... more Premna odorata Blanco (Lamiaceae) is a medicinal plant traditionally used in Albay Province, in southeastern Luzon, Philippines to treat tuberculosis. This study aimed to determine the antitubercular property of the crude extract and sub-extracts of the leaves, and to isolate the bioactive principles from the active fractions. Through extraction, solvent polarity-based fractionation and silica gel chromatography purification of the DCM sub-extract, compound mixtures from the bioactive fractions were isolated and screened for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv using the colorimetric Microplate Alamar Blue assay (MABA). The crude methanolic extract and sub-extracts showed poor inhibitory activity against Mycobacterium tuberculosis H37Rv (MIC≥128µg/mL). However, increased inhibitory potency was observed for fractions eluted from the DCM sub-extract (MIC=54 to 120µg/mL). Further purification of the most active fraction (MIC=54µg/mL) led to the isolation of a 1-heneicosyl formate (1), 4:1 mixture of β-sitosterol (2), stigmasterol (3) and diosmetin (4), which were identified through GC-MS analysis (with dereplication) and NMR experiments. The MIC of compound 1 was 8µg/mL. The results of this study provide scientific basis for the traditional use of Premna odorata as treatment for tuberculosis.
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International Journal of Antimicrobial Agents, 2007
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European Journal of Medicinal Chemistry, 2011
Globospiramine (1), a new spirobisindole alkaloid possessing an Aspidosperma-Aspidosperma skeleto... more Globospiramine (1), a new spirobisindole alkaloid possessing an Aspidosperma-Aspidosperma skeleton, together with deoxyvobtusine (2), deoxyvobtusine lactone (3), vobtusine lactone (4) and lupeol (5), were isolated and identified from Voacanga globosa through a bioassay-guided purification. The gross structure and absolute stereochemistry of 1 were established by circular dichroism spectroscopy, HR-MS and unambiguous NMR spectroscopic experiments. In addition, a new biogenetic pathway for the formation of the spiro-Aspidosperma-Aspidosperma skeleton is proposed. Alkaloid 1 showed potent antituberculosis activity against Mycobacterium tuberculosis H(37)Rv as evidenced in microplate Alamar blue assay (MIC = 4 μg/mL) and low-oxygen recovery assay (LORA (MIC = 5.2 μg/mL). The bisindole alkaloids also exhibited promising activity against acetylcholinesterase and, especially butyrylcholinesterase, with deoxyvobtusine (2) (IC(50) = 6.2 μM) as the most strongly inhibiting compound. This study extends the variety of alkaloid structural platforms which exhibit antimycobacterial and anticholinesterase activity.
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Biochemical Systematics and Ecology, 2008
Clerodendrum quadriloculare Merr (Verbenaceae), an endemic Philippine medicinal plant, is locally... more Clerodendrum quadriloculare Merr (Verbenaceae), an endemic Philippine medicinal plant, is locally known as ''bagauak''. It is a small tree that thrives in several provinces of the Luzon Island. The leaves are ethnomedically used to treat wounds and ulcer, and employed in tonic baths (Quisumbing, 1978). Fresh leaves were collected in the lowland of Mt. Cordillera, Ilocos Sur Province in December 2004. The plant was identified by Asst. Prof. Rosie A. Madulid and a voucher specimen (USTH4899) is deposited at the UST Herbarium, Botany ...
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Biochemical Systematics and Ecology, 2010
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Molecules, 2020
The -glucosidase and lipase inhibitory activities of three phenalenones (1–3) and one phenylprop... more The -glucosidase and lipase inhibitory activities of three phenalenones (1–3) and one phenylpropanoid (4) from the ethyl acetate extracts of a Pseudolophiosptoma sp. are described. They represent the first reported secondary metabolites from the genus Pseudolophiostoma. Scleroderolide (1) and sclerodione (2) exhibited potent -glucosidase and porcine lipase inhibitory activity during primary screening, with better IC50s compared to the positive controls, N-deoxynojirimycin and orlistat. In silico techniques were employed to validate the probable biological targets and elucidate the mechanism of actions of phenalenones 1 and 2. Both compounds exhibited strong binding affinities to both -glucosidase and porcine lipase through H-bonding and - interactions. Interestingly, favorable in silico ADME properties such as gastrointestinal absorption were also predicted using computational programmes.
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Biomolecules, 2020
Pseudopalawania siamensis gen. et sp. nov., from northern Thailand, is introduced based on multi-... more Pseudopalawania siamensis gen. et sp. nov., from northern Thailand, is introduced based on multi-gene analyses and morphological comparison. An isolate was fermented in yeast malt culture broth and explored for its secondary metabolite production. Chromatographic purification of the crude ethyl acetate (broth) extract yielded four tetrahydroxanthones comprised of a new heterodimeric bistetrahydroxanthone, pseudopalawanone (1), two known dimeric derivatives, 4,4′-secalonic acid D (2) and penicillixanthone A (3), the corresponding monomeric tetrahydroxanthone paecilin B (4), and the known benzophenone, cephalanone F (5). Compounds 1–3 showed potent inhibitory activity against Gram-positive bacteria. Compounds 2 and 3 were inhibitory against Bacillus subtilis with minimum inhibitory concentrations (MIC) of 1.0 and 4.2 μg/mL, respectively. Only compound 2 showed activity against Mycobacterium smegmatis. In addition, the dimeric compounds 1–3 also showed moderate cytotoxic effects on HeLa and mouse fibroblast cell lines, which makes them less attractive as candidates for development of selectively acting antibiotics.
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Biochemical Systematics and Ecology, 2007
Uvaria rufa Blume is known locally as ''susung kalabaw&... more Uvaria rufa Blume is known locally as ''susung kalabaw'', due to the resemblance of its fruits to the mammary organ of the Philippine carabao. It is a short climbing shrub that grows in low-and medium-altitude thickets of Northern Luzon to Palawan and Mindanao. An alcoholic tincture of its roots is used ethnomedically as ecbolic (Quisumbing, 1978). Fresh leaves were collected in the forest of Mt. Cordillera, Ilocos Sur Province in October 2003. The plant was identified by Asst. Prof. Rosie A. Madulid and a voucher specimen (USTH4897) is ...
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Synlett, 2008
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Philippine Journal of Systematic Biology
The taxonomic classification and unique characteristics of an air-borne actinomycete exhibiting a... more The taxonomic classification and unique characteristics of an air-borne actinomycete exhibiting a dark orange pigmentation were determined by polyphasic analysis. The colony appeared as a contaminant in an agar plate culture of the marine luminous bacterium: Vibrio fischeri USTCMS 1026. Subsequent investigation identified the actinomycete contaminant as MP 1066 for Mycobacterium phlei USTCMS 1066 but was later found to have morphological, physiological, biochemical and genotypic characteristics compatible with member species of the genus Gordonia. BLAST comparison of MP 1066 yielded 100% 16S rDNA sequence alignment with Gordonia terrae so the strain was renamed as Gordonia terrae USTCMS 1066. Its antimicrobial susceptibility profile is similar to that of the pathogenic mycobacteria yielding small MICs and large inhibition zones against the antibiotics: ampicillin (AMP), azithromycin (AZT), amoxicillin-clavulanic acid (AUC), ciprofloxacin (CIP), ethambutol (ETHAM), isoniazid (INH), r...
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Opioids such as morphine, codeine, and oxycodone are extracts or analogs isolated from a single s... more Opioids such as morphine, codeine, and oxycodone are extracts or analogs isolated from a single source: the opium poppy. For a long time, it was believed to be nature’s only source of opioids. But it now appears that biological diversity has evolved an alternative source of opioid compounds—those derived from the plant Mitragyna speciosa. This plant, known as Kratom in Thailand or Biak-Biak in Malaysia, has long been used locally as treatment for pain, fever reduction, diarrhea, and even depression. Kratom and Other Mitragynines: The Chemistry and Pharmacology of Opioids from a Non-Opium Source presents an introduction to the chemical and biological properties of alkaloids isolated from M. speciosa as well as their synthetic analogs. The book covers various topics including phytochemistry, medicinal chemistry, and pharmacology. Current research, analgesic effects, and addiction potential are also discussed. As the first extensive text on the basic science and clinical use of Kratom,...
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Natural product communications, 2012
A synthesis of a new alkaloid-fullerene conjugate (1) is reported. The reaction was carried out b... more A synthesis of a new alkaloid-fullerene conjugate (1) is reported. The reaction was carried out by photoinduced [3+2] cycloaddition of the Alstonia indole alkaloid, 6,7-seco-angustilobine B (2), to fullerene[C60] (3) under aerobic conditions. The major monoaddition photoadduct (1) was characterized unambiguously by UV, IR, MALDI-TOFMS and NMR experiments. A mechanism highlighted by sequential photoinduced electron transfer andradical recombination pathways is also proposed. No significant enhancement in inhibition against M. tuberculosis H37Rv was observed for 1 compared with its parent compounds 2 and 3.
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Philippine Journal of Systematic Biology
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Asian Pacific Journal of Tropical Medicine, 2012
To investigate the inhibitory activity of the chloroform extract, petroleum ether and chloroform ... more To investigate the inhibitory activity of the chloroform extract, petroleum ether and chloroform sub-extracts, lead-acetate treated chloroform extract, fractions and secondary metabolites of Uvaria rufa (U. rufa) against Mycobacterium tuberculosis (M. tuberculosis) H(37)Rv. The antituberculosis susceptibility assay was carried out using the colorimetric Microplate Alamar blue assay (MABA). In addition, the cytotoxicity of the most active fraction was evaluated using the VERO cell toxicity assay. The in vitro inhibitory activity against M. tuberculosis H(37)Rv increased as purification progressed to fractionation (MIC up to 23 μg/mL). The chloroform extract and its sub-extracts showed moderate toxicity while the most active fraction from chloroform sub-extract exhibited no cytotoxicity against VERO cells. Meanwhile, the lead acetate-treated crude chloroform extract and its fractions showed complete inhibitions (100%) with MIC values up to 8 μg/mL. Phytochemical screening of the most active fraction showed, in general, the presence of terpenoids, steroids and phenolic compounds. Evaluation of the antimycobacterial activity of known secondary metabolites isolated showed no promising inhibitory activity against the test organism. The present results demonstrate the potential of U. rufa as a phytomedicinal source of compounds that may exhibit promising antituberculosis activity. In addition, elimination of polar pigments revealed enhanced inhibition against M. tuberculosis H(37)Rv. While several compounds known for this plant did not show antimycobacterial activity, the obtained results are considered sufficient reason for further study to isolate the metabolites from U. rufa responsible for the antitubercular activity.
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Phytochemistry, 2005
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Journal of Ethnopharmacology, 2014
Premna odorata Blanco (Lamiaceae) is a medicinal plant traditionally used in Albay Province, in s... more Premna odorata Blanco (Lamiaceae) is a medicinal plant traditionally used in Albay Province, in southeastern Luzon, Philippines to treat tuberculosis. This study aimed to determine the antitubercular property of the crude extract and sub-extracts of the leaves, and to isolate the bioactive principles from the active fractions. Through extraction, solvent polarity-based fractionation and silica gel chromatography purification of the DCM sub-extract, compound mixtures from the bioactive fractions were isolated and screened for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv using the colorimetric Microplate Alamar Blue assay (MABA). The crude methanolic extract and sub-extracts showed poor inhibitory activity against Mycobacterium tuberculosis H37Rv (MIC≥128µg/mL). However, increased inhibitory potency was observed for fractions eluted from the DCM sub-extract (MIC=54 to 120µg/mL). Further purification of the most active fraction (MIC=54µg/mL) led to the isolation of a 1-heneicosyl formate (1), 4:1 mixture of β-sitosterol (2), stigmasterol (3) and diosmetin (4), which were identified through GC-MS analysis (with dereplication) and NMR experiments. The MIC of compound 1 was 8µg/mL. The results of this study provide scientific basis for the traditional use of Premna odorata as treatment for tuberculosis.
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International Journal of Antimicrobial Agents, 2007
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European Journal of Medicinal Chemistry, 2011
Globospiramine (1), a new spirobisindole alkaloid possessing an Aspidosperma-Aspidosperma skeleto... more Globospiramine (1), a new spirobisindole alkaloid possessing an Aspidosperma-Aspidosperma skeleton, together with deoxyvobtusine (2), deoxyvobtusine lactone (3), vobtusine lactone (4) and lupeol (5), were isolated and identified from Voacanga globosa through a bioassay-guided purification. The gross structure and absolute stereochemistry of 1 were established by circular dichroism spectroscopy, HR-MS and unambiguous NMR spectroscopic experiments. In addition, a new biogenetic pathway for the formation of the spiro-Aspidosperma-Aspidosperma skeleton is proposed. Alkaloid 1 showed potent antituberculosis activity against Mycobacterium tuberculosis H(37)Rv as evidenced in microplate Alamar blue assay (MIC = 4 μg/mL) and low-oxygen recovery assay (LORA (MIC = 5.2 μg/mL). The bisindole alkaloids also exhibited promising activity against acetylcholinesterase and, especially butyrylcholinesterase, with deoxyvobtusine (2) (IC(50) = 6.2 μM) as the most strongly inhibiting compound. This study extends the variety of alkaloid structural platforms which exhibit antimycobacterial and anticholinesterase activity.
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Biochemical Systematics and Ecology, 2008
Clerodendrum quadriloculare Merr (Verbenaceae), an endemic Philippine medicinal plant, is locally... more Clerodendrum quadriloculare Merr (Verbenaceae), an endemic Philippine medicinal plant, is locally known as ''bagauak''. It is a small tree that thrives in several provinces of the Luzon Island. The leaves are ethnomedically used to treat wounds and ulcer, and employed in tonic baths (Quisumbing, 1978). Fresh leaves were collected in the lowland of Mt. Cordillera, Ilocos Sur Province in December 2004. The plant was identified by Asst. Prof. Rosie A. Madulid and a voucher specimen (USTH4899) is deposited at the UST Herbarium, Botany ...
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Biochemical Systematics and Ecology, 2010
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Molecules, 2020
The -glucosidase and lipase inhibitory activities of three phenalenones (1–3) and one phenylprop... more The -glucosidase and lipase inhibitory activities of three phenalenones (1–3) and one phenylpropanoid (4) from the ethyl acetate extracts of a Pseudolophiosptoma sp. are described. They represent the first reported secondary metabolites from the genus Pseudolophiostoma. Scleroderolide (1) and sclerodione (2) exhibited potent -glucosidase and porcine lipase inhibitory activity during primary screening, with better IC50s compared to the positive controls, N-deoxynojirimycin and orlistat. In silico techniques were employed to validate the probable biological targets and elucidate the mechanism of actions of phenalenones 1 and 2. Both compounds exhibited strong binding affinities to both -glucosidase and porcine lipase through H-bonding and - interactions. Interestingly, favorable in silico ADME properties such as gastrointestinal absorption were also predicted using computational programmes.
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Biomolecules, 2020
Pseudopalawania siamensis gen. et sp. nov., from northern Thailand, is introduced based on multi-... more Pseudopalawania siamensis gen. et sp. nov., from northern Thailand, is introduced based on multi-gene analyses and morphological comparison. An isolate was fermented in yeast malt culture broth and explored for its secondary metabolite production. Chromatographic purification of the crude ethyl acetate (broth) extract yielded four tetrahydroxanthones comprised of a new heterodimeric bistetrahydroxanthone, pseudopalawanone (1), two known dimeric derivatives, 4,4′-secalonic acid D (2) and penicillixanthone A (3), the corresponding monomeric tetrahydroxanthone paecilin B (4), and the known benzophenone, cephalanone F (5). Compounds 1–3 showed potent inhibitory activity against Gram-positive bacteria. Compounds 2 and 3 were inhibitory against Bacillus subtilis with minimum inhibitory concentrations (MIC) of 1.0 and 4.2 μg/mL, respectively. Only compound 2 showed activity against Mycobacterium smegmatis. In addition, the dimeric compounds 1–3 also showed moderate cytotoxic effects on HeLa and mouse fibroblast cell lines, which makes them less attractive as candidates for development of selectively acting antibiotics.
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