EMELINA MANDIA | De La Salle University (original) (raw)

Papers by EMELINA MANDIA

Phytochemistry Letters, Nov 1, 2013

ABSTRACT Dysoxylum mollissimum Blume, the accepted name of the species known by more than a dozen... more ABSTRACT Dysoxylum mollissimum Blume, the accepted name of the species known by more than a dozen names has been extensively studied for its chemical constituents under the name Dysoxylum hainanense Merr. Congruent with the observation that the chemical constituents of this species might be affected by its geographic distribution, the leaf samples of this species from Quezon Province, Philippines was investigated. The dichloromethane extract of the air-dried leaves of Dysoxylum mollissimum Blume afforded four new glabretal-type triterpenoids (1a-2b) along with the known compounds, 24,25-epoxy-3β,23-dihydroxy-7-tirucallene (3), squalene, polyprenol, linoleic acid and lutein. The structures of 1a-2b were elucidated by extensive 1D and 2D NMR spectroscopy and confirmed by mass spectrometry.

Pharmaceutical and Clinical Research, 2016

Chemical investigation of the dichloromethane extracts of Ficus septica Burm.f. led to the isolat... more Chemical investigation of the dichloromethane extracts of Ficus septica Burm.f. led to the isolation of β-sitosteryl-3β-glucopyranoside-6’-O-fatty acid esters (1), α-amyrin fatty acid esters (2), and a mixture of β-sitosterol (3a) and stigmasterol (3b) in a 5: 2 ratios from the twigs; and 3a, β-amyrin (4), and long chain saturated fatty alcohols (5) from the leaves. The structures of 1-5 were identified by NMR spectroscopy. © 2016, International Journal of Pharmaceutical and Clinical Research. All rights reserved

Chemistry of Natural Compounds, Mar 1, 2014

Certain strains of algae yield adequate amounts of protein, and the microalgae species, Chlorococ... more Certain strains of algae yield adequate amounts of protein, and the microalgae species, Chlorococcum infusionum, is reported to have 50% protein yield which could alleviate food shortage. However, limited studies about this strain restricts its potential for food production. Furthermore, in algal protein processing, the drying process consumes large amounts of energy. This study investigated the drying characteristics of C. infusionum to analyze its drying time and drying behavior. A definitive screening design of experiment used temperatures of 40°C, 55°C, and 70°C, absolute pressures of 20 kPa, 50 kPa, and 80 kPa, and microalgae thicknesses of 3 mm, 5 mm, and 7 mm. Thin-layer specimens are placed on petri dishes for vacuum drying, and data is automatically collected using an Arduino microcontroller. Page, Modified Page, Henderson-Pabis, Two-term, and Aghbashlo models are used, and a proposed model is constructed to improve the goodness of fit of the experimental data with the mathematical model. Newton-Rhapson method was used to fit the experimental data with the mathematical models, and the coefficient of determination (>0.989), root mean square error (<2.7%), and reduced chi-square (<0.001) are computed to analyze the goodness of fit of each model. All models exhibited good fit with the experimental data, and the proposed model was verified to best represent the drying characteristics of C. infusionum based on t-tests. The drying curves of C. infusionum is observed only in the falling-rate period and the degree of the effects of temperature, pressure, and thickness on drying time and drying rate are investigated.

Natural Product Research, Jun 15, 2008

The air-dried leaves of Tectona philippinensis, an endemic and endangered Philippine medicinal pl... more The air-dried leaves of Tectona philippinensis, an endemic and endangered Philippine medicinal plant, afforded 5-hydroxy-3,7,4&amp;amp;amp;amp;amp;amp;#39;-trimethoxyflavone (1), 5,4&amp;amp;amp;amp;amp;amp;#39;-dihydroxy-3,7-dimethoxyflavone (2), squalene (3), a mixture of lupeol (4a) and beta-amyrin (4b), chlorophyllide a (5), and hydrocarbons. Antimicrobial tests on 1 and 2 indicated low antifungal activity against the fungi, Candida albicans and Trichophyton mentagrophytes. Compound 1 was also found to have low antibacterial activity against Escherichia coli and Pseudomonas aeruginosa.

Chemistry of Natural Compounds, 2015

journal of applied pharmaceutical science, 2015

Chemistry of Natural Compounds, 2015

Pharmaceutical and Clinical Research, 2016

Chemical investigation of the dichloromethane extracts of Ficus ampelas Burm.f. has led to the is... more Chemical investigation of the dichloromethane extracts of Ficus ampelas Burm.f. has led to the isolation of squalene (1), mixtures of β-amyrin fatty acid esters (2a) and α-amyrin fatty acid esters (2b) in a 1:2 ratio and β-sitosterol (3a) and stigmasterol (3b) in a 2:1 ratio, chlorophyll a (4), and saturated fatty acids (5) from the twigs; and 5, β-sitosteryl-3β-glucopyranoside-6β-O-fatty acid esters (6), and long-chain fatty alcohols (7) from the fruit. The structures of 1-7 were identified by comparison of their NMR data with those reported in the literature.

Chemistry of Natural Compounds, Nov 1, 2015

Ten out of the 75 known Malesian species of Knema (Family Myristicaceae) occur in the Philippines... more Ten out of the 75 known Malesian species of Knema (Family Myristicaceae) occur in the Philippines [1, 2]. Of these, seven taxa are endemic to the country, mostly occurring in the island of Luzon [1]. Among these taxa is Knema stellata subsp. cryptocaryoides (Elmer) W. J. de Wilde, locally known as durogo. It is a medium-size dioecious tree growing in the lowland forests of Luzon, Sibuyan, and Mindanao. Its wood is locally used for light construction, plywood production, wall paneling, making matchboxes, splints, crates, and wooden patterns, and in the manufacture of wrapping and writing papers [3]. Interestingly, its seeds contain oil that locals use for illumination purposes [3]. Like all other endemic Philippine Knema, this particular subspecies has not been the subject of any chemical study. This study is part of our research on the chemical constituents of trees endemic to the Philippines. We earlier reported the chemical constituents of Cinnamomum utile [4], C. griffithii [5], C. rupestre, C. nanophyllum [6], C. trichophyllum [7], Ardisia squamulosa [8], Ficus linearifolia and F. triangularis [9], F. pseudopalma and F. ulmifolia [10], and F. odorata [11]. We report herein the isolation and structure elucidation of mixtures of 2-[(Z)-heptadec-8-enyl]-6-hydroxybenzoic acid (1a) and 2-[(Z)-pentadec-8-enyl]-6-hydroxybenzoic acid (1b); 3-(heptadec-8-enyl)phenol (2a), 3-(pentadec-8-enyl)phenol (2b), and 3-pentadecylphenol (2c); and saturated long-chain 4-hydroxycinnamate fatty acid esters (3) and -stigmasterol (4) from Knema stellata subsp. cryptocaryoides. This is the first report on the isolation of these compounds from Knema stellata subsp. cryptocaryoides. Samples of Knema stellata subsp. cryptocaryoides were collected from a private farm in Sitio Usiwan, Barangay Palola, Lucban, Quezon in March 2012 by Maryl V. Arceta and Leah D. J. Madrazo of the Southern Luzon State University (SLSU) in Lucban, Quezon. Within this private farm is a patch of secondary forest at 620 m asl, which interestingly harbors a number of endemic species. Voucher specimens were collected and identified by one of the authors (EHM) with collection #903 and deposited at De La Salle University, Manila. The air-dried leaves (330 g) of Knema stellata subsp. cryptocaryoides were ground in a blender, soaked in CH2Cl2 for 3 days, and then filtered. The air-dried stems (255 g) were chopped into small pieces, soaked in CH2Cl2 for 3 days, and then filtered. The filtrates were concentrated under vacuum to afford the crude extracts: 12 g (leaves) and 8 g (stems). The crude extracts were fractionated by silica gel chromatography using increasing proportions of acetone in CH2Cl2 (10% increment) as eluents.

Journal of Clean Technologies and Environmental Policy, 2020

Despite the many advantages of third-generation biofuels, there are still numerous opportunities ... more Despite the many advantages of third-generation biofuels, there are still numerous opportunities to improve their production efficiency and streamline their commercialization. The unpredictability of cultivating biomass is a major challenge to consistent, efficient production. In particular, the cultivation of Spirulina platensis biomass for biofuel production is affected by various environmental factors such as light, temperature, pH and the nutrient concentration of water. Since controlling these factors is energy intensive, a biomass prediction model would be helpful in anticipating biomass production and in indicating necessary adjustments to the process to improve yield. In this case, earlier is clearly better. This study developed a machine learning-based early prediction model which identifies the earliest time during cultivation that the process parameters optical density and pH can accurately be used to predict biomass yield. In the case study, the early prediction model predicted the final biomass yield (on the 23 rd day) by the 8 th day of cultivation using ridge regression. Furthermore, an application of this model in pH control led to a 54.1% average improvement in biomass yield. This model may be used to monitor cultivation batches allowing problems (i.e., low yield) to be identified early. It can also be applied in process simulation and optimization to improve biomass yield. In summary, mathematical modelling can make the unpredictable biomass process more predictable, and improve production efficiency.

Philippine Quarterly of Culture and Society, 2004

Gardens Bulletin Singapore, 2001

A recent, small collection of mosses from Mt. Halcon, Mindoro Island, the Philippines, has yielde... more A recent, small collection of mosses from Mt. Halcon, Mindoro Island, the Philippines, has yielded two new records for the country (Rhacocarpus alpinus (Wright) Par. and Dicranoloma daymannianum Bartr.) and eight new records for the island. Relevant ecological, morphological and biogeographical notes for the 15 species collected are provided.

Journal of Natural Products, Feb 16, 2008

The air-dried leaves of Tectona philippinensis, an endemic and endangered Philippine medicinal tr... more The air-dried leaves of Tectona philippinensis, an endemic and endangered Philippine medicinal tree, afforded four new chromomoric acid derivatives (1, 2, 3a, and 3b). Their structures were elucidated by extensive 1D and 2D NMR spectroscopy. Antimicrobial testing was carried out on 1-3 against a panel of bacteria and fungi.

Pharmaceutical and Clinical Research, 2016

Chemical investigation of the dichloromethane extracts of Ficus septica Burm.f. led to the isolat... more Chemical investigation of the dichloromethane extracts of Ficus septica Burm.f. led to the isolation of β-sitosteryl-3β-glucopyranoside-6’-O-fatty acid esters (1), α-amyrin fatty acid esters (2), and a mixture of β-sitosterol (3a) and stigmasterol (3b) in a 5: 2 ratios from the twigs; and 3a, β-amyrin (4), and long chain saturated fatty alcohols (5) from the leaves. The structures of 1-5 were identified by NMR spectroscopy. © 2016, International Journal of Pharmaceutical and Clinical Research. All rights reserved

Phytochemistry Letters, Nov 1, 2013

ABSTRACT Dysoxylum mollissimum Blume, the accepted name of the species known by more than a dozen... more ABSTRACT Dysoxylum mollissimum Blume, the accepted name of the species known by more than a dozen names has been extensively studied for its chemical constituents under the name Dysoxylum hainanense Merr. Congruent with the observation that the chemical constituents of this species might be affected by its geographic distribution, the leaf samples of this species from Quezon Province, Philippines was investigated. The dichloromethane extract of the air-dried leaves of Dysoxylum mollissimum Blume afforded four new glabretal-type triterpenoids (1a-2b) along with the known compounds, 24,25-epoxy-3β,23-dihydroxy-7-tirucallene (3), squalene, polyprenol, linoleic acid and lutein. The structures of 1a-2b were elucidated by extensive 1D and 2D NMR spectroscopy and confirmed by mass spectrometry.

Pharmaceutical and Clinical Research, 2016

Chemical investigation of the dichloromethane extracts of Ficus septica Burm.f. led to the isolat... more Chemical investigation of the dichloromethane extracts of Ficus septica Burm.f. led to the isolation of β-sitosteryl-3β-glucopyranoside-6’-O-fatty acid esters (1), α-amyrin fatty acid esters (2), and a mixture of β-sitosterol (3a) and stigmasterol (3b) in a 5: 2 ratios from the twigs; and 3a, β-amyrin (4), and long chain saturated fatty alcohols (5) from the leaves. The structures of 1-5 were identified by NMR spectroscopy. © 2016, International Journal of Pharmaceutical and Clinical Research. All rights reserved

Chemistry of Natural Compounds, Mar 1, 2014

Certain strains of algae yield adequate amounts of protein, and the microalgae species, Chlorococ... more Certain strains of algae yield adequate amounts of protein, and the microalgae species, Chlorococcum infusionum, is reported to have 50% protein yield which could alleviate food shortage. However, limited studies about this strain restricts its potential for food production. Furthermore, in algal protein processing, the drying process consumes large amounts of energy. This study investigated the drying characteristics of C. infusionum to analyze its drying time and drying behavior. A definitive screening design of experiment used temperatures of 40°C, 55°C, and 70°C, absolute pressures of 20 kPa, 50 kPa, and 80 kPa, and microalgae thicknesses of 3 mm, 5 mm, and 7 mm. Thin-layer specimens are placed on petri dishes for vacuum drying, and data is automatically collected using an Arduino microcontroller. Page, Modified Page, Henderson-Pabis, Two-term, and Aghbashlo models are used, and a proposed model is constructed to improve the goodness of fit of the experimental data with the mathematical model. Newton-Rhapson method was used to fit the experimental data with the mathematical models, and the coefficient of determination (>0.989), root mean square error (<2.7%), and reduced chi-square (<0.001) are computed to analyze the goodness of fit of each model. All models exhibited good fit with the experimental data, and the proposed model was verified to best represent the drying characteristics of C. infusionum based on t-tests. The drying curves of C. infusionum is observed only in the falling-rate period and the degree of the effects of temperature, pressure, and thickness on drying time and drying rate are investigated.

Natural Product Research, Jun 15, 2008

The air-dried leaves of Tectona philippinensis, an endemic and endangered Philippine medicinal pl... more The air-dried leaves of Tectona philippinensis, an endemic and endangered Philippine medicinal plant, afforded 5-hydroxy-3,7,4&amp;amp;amp;amp;amp;amp;#39;-trimethoxyflavone (1), 5,4&amp;amp;amp;amp;amp;amp;#39;-dihydroxy-3,7-dimethoxyflavone (2), squalene (3), a mixture of lupeol (4a) and beta-amyrin (4b), chlorophyllide a (5), and hydrocarbons. Antimicrobial tests on 1 and 2 indicated low antifungal activity against the fungi, Candida albicans and Trichophyton mentagrophytes. Compound 1 was also found to have low antibacterial activity against Escherichia coli and Pseudomonas aeruginosa.

Chemistry of Natural Compounds, 2015

journal of applied pharmaceutical science, 2015

Chemistry of Natural Compounds, 2015

Pharmaceutical and Clinical Research, 2016

Chemical investigation of the dichloromethane extracts of Ficus ampelas Burm.f. has led to the is... more Chemical investigation of the dichloromethane extracts of Ficus ampelas Burm.f. has led to the isolation of squalene (1), mixtures of β-amyrin fatty acid esters (2a) and α-amyrin fatty acid esters (2b) in a 1:2 ratio and β-sitosterol (3a) and stigmasterol (3b) in a 2:1 ratio, chlorophyll a (4), and saturated fatty acids (5) from the twigs; and 5, β-sitosteryl-3β-glucopyranoside-6β-O-fatty acid esters (6), and long-chain fatty alcohols (7) from the fruit. The structures of 1-7 were identified by comparison of their NMR data with those reported in the literature.

Chemistry of Natural Compounds, Nov 1, 2015

Ten out of the 75 known Malesian species of Knema (Family Myristicaceae) occur in the Philippines... more Ten out of the 75 known Malesian species of Knema (Family Myristicaceae) occur in the Philippines [1, 2]. Of these, seven taxa are endemic to the country, mostly occurring in the island of Luzon [1]. Among these taxa is Knema stellata subsp. cryptocaryoides (Elmer) W. J. de Wilde, locally known as durogo. It is a medium-size dioecious tree growing in the lowland forests of Luzon, Sibuyan, and Mindanao. Its wood is locally used for light construction, plywood production, wall paneling, making matchboxes, splints, crates, and wooden patterns, and in the manufacture of wrapping and writing papers [3]. Interestingly, its seeds contain oil that locals use for illumination purposes [3]. Like all other endemic Philippine Knema, this particular subspecies has not been the subject of any chemical study. This study is part of our research on the chemical constituents of trees endemic to the Philippines. We earlier reported the chemical constituents of Cinnamomum utile [4], C. griffithii [5], C. rupestre, C. nanophyllum [6], C. trichophyllum [7], Ardisia squamulosa [8], Ficus linearifolia and F. triangularis [9], F. pseudopalma and F. ulmifolia [10], and F. odorata [11]. We report herein the isolation and structure elucidation of mixtures of 2-[(Z)-heptadec-8-enyl]-6-hydroxybenzoic acid (1a) and 2-[(Z)-pentadec-8-enyl]-6-hydroxybenzoic acid (1b); 3-(heptadec-8-enyl)phenol (2a), 3-(pentadec-8-enyl)phenol (2b), and 3-pentadecylphenol (2c); and saturated long-chain 4-hydroxycinnamate fatty acid esters (3) and -stigmasterol (4) from Knema stellata subsp. cryptocaryoides. This is the first report on the isolation of these compounds from Knema stellata subsp. cryptocaryoides. Samples of Knema stellata subsp. cryptocaryoides were collected from a private farm in Sitio Usiwan, Barangay Palola, Lucban, Quezon in March 2012 by Maryl V. Arceta and Leah D. J. Madrazo of the Southern Luzon State University (SLSU) in Lucban, Quezon. Within this private farm is a patch of secondary forest at 620 m asl, which interestingly harbors a number of endemic species. Voucher specimens were collected and identified by one of the authors (EHM) with collection #903 and deposited at De La Salle University, Manila. The air-dried leaves (330 g) of Knema stellata subsp. cryptocaryoides were ground in a blender, soaked in CH2Cl2 for 3 days, and then filtered. The air-dried stems (255 g) were chopped into small pieces, soaked in CH2Cl2 for 3 days, and then filtered. The filtrates were concentrated under vacuum to afford the crude extracts: 12 g (leaves) and 8 g (stems). The crude extracts were fractionated by silica gel chromatography using increasing proportions of acetone in CH2Cl2 (10% increment) as eluents.

Journal of Clean Technologies and Environmental Policy, 2020

Despite the many advantages of third-generation biofuels, there are still numerous opportunities ... more Despite the many advantages of third-generation biofuels, there are still numerous opportunities to improve their production efficiency and streamline their commercialization. The unpredictability of cultivating biomass is a major challenge to consistent, efficient production. In particular, the cultivation of Spirulina platensis biomass for biofuel production is affected by various environmental factors such as light, temperature, pH and the nutrient concentration of water. Since controlling these factors is energy intensive, a biomass prediction model would be helpful in anticipating biomass production and in indicating necessary adjustments to the process to improve yield. In this case, earlier is clearly better. This study developed a machine learning-based early prediction model which identifies the earliest time during cultivation that the process parameters optical density and pH can accurately be used to predict biomass yield. In the case study, the early prediction model predicted the final biomass yield (on the 23 rd day) by the 8 th day of cultivation using ridge regression. Furthermore, an application of this model in pH control led to a 54.1% average improvement in biomass yield. This model may be used to monitor cultivation batches allowing problems (i.e., low yield) to be identified early. It can also be applied in process simulation and optimization to improve biomass yield. In summary, mathematical modelling can make the unpredictable biomass process more predictable, and improve production efficiency.

Philippine Quarterly of Culture and Society, 2004

Gardens Bulletin Singapore, 2001

A recent, small collection of mosses from Mt. Halcon, Mindoro Island, the Philippines, has yielde... more A recent, small collection of mosses from Mt. Halcon, Mindoro Island, the Philippines, has yielded two new records for the country (Rhacocarpus alpinus (Wright) Par. and Dicranoloma daymannianum Bartr.) and eight new records for the island. Relevant ecological, morphological and biogeographical notes for the 15 species collected are provided.

Journal of Natural Products, Feb 16, 2008

The air-dried leaves of Tectona philippinensis, an endemic and endangered Philippine medicinal tr... more The air-dried leaves of Tectona philippinensis, an endemic and endangered Philippine medicinal tree, afforded four new chromomoric acid derivatives (1, 2, 3a, and 3b). Their structures were elucidated by extensive 1D and 2D NMR spectroscopy. Antimicrobial testing was carried out on 1-3 against a panel of bacteria and fungi.

Pharmaceutical and Clinical Research, 2016

Chemical investigation of the dichloromethane extracts of Ficus septica Burm.f. led to the isolat... more Chemical investigation of the dichloromethane extracts of Ficus septica Burm.f. led to the isolation of β-sitosteryl-3β-glucopyranoside-6’-O-fatty acid esters (1), α-amyrin fatty acid esters (2), and a mixture of β-sitosterol (3a) and stigmasterol (3b) in a 5: 2 ratios from the twigs; and 3a, β-amyrin (4), and long chain saturated fatty alcohols (5) from the leaves. The structures of 1-5 were identified by NMR spectroscopy. © 2016, International Journal of Pharmaceutical and Clinical Research. All rights reserved