Indonesian Journal of Forestry Research Vol.
10 No.
October 2023, 195-205
ISSN 2355-7079/E-ISSN 2406-8195
CHEMICAL CONSTITUENTS OF Melaleuca leucadendron Linn.
LEAF
ESSENTIAL OILS QUALITY UNDER DIFFERENT COLLECTING
TIMES IN KPH YOGYAKARTA.
GUNUNGKIDUL.
INDONESIA
Rizki Arisandi1*.
Rini Pujiarti1.
Ganis Lukmandaru1 and Budi Mulyana2 Department of Forest Product Technology.
Faculty of Forestry.
Universitas Gadjah Mada.
Jl.
Agro No.
Bulaksumur.
Yogyakarta 55281.
Indonesia 6274 550541 Department of Forest Management.
Faculty of Forestry.
Universitas Gadjah Mada.
Jl.
Agro No.
Bulaksumur.
Yogyakarta 55281.
Indonesia 6274 550541 Received: 30 September 2022.
Revised: 21 October 20223.
Accepted: 21 October 2023 CHEMICAL CONSTITUENTS OF Melaleuca leucadendron Linn.
LEAF ESSENTIAL OILS QUALITY
UNDER DIFFERENT COLLECTING TIMES IN KPH YOGYAKARTA.
GUNUNGKIDUL,
INDONESIA.
Melaleuca leucadendron Linn is one of Indonesia's most important non-timber forest products as a commercial essential oil.
The aim of this study was to investigate the variation of compounds in M.
leucadendron essential oils when leaves were collected at different times from August 2017 to April 2018 at the Yogyakarta Forest Management Unit (FMU).
The essential oils were isolated by steam distillation and analyzed by gas chromatography-mass spectrometry (GC-MS).
A total of 13 constituents were identified with major compounds, i.
, 1.
8-cineole .
8 to 76.
0%).
D ( )-limonene .
40 to 12.
1%), p-cymene .
9%) and -terpineol .
98 to 9.
98%).
The results showed that the weather conditions in the higher rainfall and flowering were favorable for the production of essential oil (Marc.
and increased the major compounds, especially from November to January .
ith the exception of -terpineol, which was found to be higher in Septembe.
In contrast to these main compounds, -pinene, -pinene, and humulene are used as marker compounds to distinguish between the lowest and highest period.
In addition, it is also noted that the flowering stage affects the monthly variation of the major compounds.
Keywords: Melaleuca leucadendron.
Myrtaceae.
Seasonal variation.
Leaf essential oil, 1.
8-cineole KONSTITUEN KIMIA Melaleuca leucadendron Linn.
KUALITAS MINYAK ATSIRI DAUN PADA
WAKTU PENGUMPULAN YANG BERBEDA DI KPH YOGYAKARTA.
GUNUNGKIDUL,
INDONESIA.
Melaleuca leucadendron Linn merupakan salah satu hasil hutan non kayu terpenting di Indonesia sebagai minyak atsiri komersial.
Tujuan dari studi ini adalah untuk menginvestigasi variasi senyawa dalam minyak atsiri M.
leucadendron ketika daun dikumpulkan pada waktu yang berbeda dari Agustus 2017 hingga April 2018 di Kesatuan Pengelolaan Hutan (KPH) Yogyakarta.
Minyak atsiri diisolasi dengan destilasi uap dan dianalisis dengan Gas chromatography-mass spectrometry (GC-MS).
Sebanyak 13 konstituen diidentifikasi dengan senyawa utama, yaitu 1,8-cineole .
,8 -76,0%).
D ( )-limonene .
,40Ae12,1%), p-cymene .
,53 - 12,9%) dan -terpineol .
,98 - 9,98%).
Hasil penelitian menunjukkan bahwa kondisi cuaca dengan curah hujan yang lebih tinggi dan berbunga, menguntungkan untuk produksi minyak atsiri (Mare.
dan meningkatkan senyawa utama, terutama dari bulan November hingga Januari .
ecuali -terpineol, yang ditemukan lebih tinggi pada bulan Septembe.
Berbeda dengan senyawa utama tersebut, -pinene, -pinene, dan humulene digunakan sebagai senyawa penanda untuk membedakan periode curah hujan rendah dan tinggi.
Selain itu, juga perlu dicatat bahwa tahap pembungaan mempengaruhi variasi bulanan senyawa utama.
Kata kunci: Melaleuca leucadendron.
Myrtaceae.
Variasi musim.
Minyak atsiri daun, 1,8-cineole Corresponding author: rizki.
arisandi@mail.
A2023 IJFR.
Open access under CC BY-NC-SA license.
doi:10.
59465/ijfr.
Indonesian Journal of Forestry Research Vol.
10 No.
October 2023, 195-205
INTRODUCTION
Melaleuca leucadendron, known as Cajuput oilproducing tree, is one of the most important commercial essential oils in Indonesia (Budiadi.
Ishii.
Sunarto, & Kanazawa, 2005.
Pujiarti.
Ohtani, & Ichiura, 2.
This plant belongs to the Myrtaceae family, which produces strongscented essential oils with useful medicinal properties from leaves, twigs, and stems by water steam distillation (Budiadi et al.
, 2005.
Farag et al.
, 2.
Melaleuca is commonly found in the islands of Java.
Moluccas.
East Nusa Tenggara, and Sulawesi Islands (Pujiarti et , 2.
leucadendron trees planted on the island of Java were first established as a pioneer tree for reforestation in 1924.
In addition, the commercial production of essential oil by the forest owner started in the 1960s (Budiadi et , 2.
It is known that the quality of M.
leucadendron essential oil depends on the yield of 1,8-cineole, a pharmacologically active component of the aromatic essential oil (Milthorpe.
Brooker.
Slee, & Nicol, 1.
Indonesia, the quality requirement of excellent leucadendron essential oil is expected to have 1,8-cineole levels ranging from 50 to 65%, as per the Indonesian National Standard (Badan Standardisasi Nasional, 2.
Certain major constituents from these plants have some biological activity and also flavor and fragrance Some factors, such as the quality of the site and the season of harvesting, can affect the quality of the essential oil (Castelo.
Del Menezzi, & Resck, 2012.
Lee.
Brooks.
Rossetto.
Henry, & Baverstock, 2.
In addition, rainfall, temperature, and humidity are also reported to affect the quality and quantity of essential oil (Usano-Alemany.
Paly-Payl, & Herryiz-Peyalver, 2014, 2016.
Pellegrini et al.
Garcya-Caparrys et al.
, 2019.
Sadono.
Soeprijadi, & Wirabuana, 2019.
Karalija.
Dahija.
Tarkowski, & ZeljkovicA, 2.
Therefore, the quality of M.
leucadendron essential oil is assumed to depend on the collecting time.
In previous
ISSN: 2355-7079/E-ISSN: 2406-8195
studies, some authors reported variations in the chemical composition of essential oils depending on the month of collection and season within the same or different families in certain species.
, such as Blepharocalyx salicifolius.
Psidium myrsinites.
Vitex trifolia var.
Purpurea and Mentha longifolia (Castelo et al.
, 2012.
Dehsheikh et al.
, 2019.
Zouari-Bouassida.
Trigui.
Makni.
Jlaiel, & Tounsi, 2.
However, to our knowledge, research related to the influence of harvesting time in different months on the chemical composition of M.
essential oil is still limited.
The influence of different ages and regions of the tree on the chemical composition and biological activity of essential oils has been relatively little studied in this species (Pujiarti et al.
, 2011, 2.
The objective of this study was to investigate the variation of the major constituents from M.
leucadendron essential oils with varying collection times in months.
In addition, variations in the chemical composition of M.
essential oil and its major compounds have also been studied.
Knowledge of the 1,8-cineole level and variation in its chemical composition may help predict the best time to collect the fresh leaves of M.
Investigation of the potential of the major compound from leucadendron will support the pharmaceutical industry, including the dairy, vitamin, and cosmetic industries.
II.
MATERIAL AND METHOD
Materials The leaves of M.
leucadendron leaves were collected 15 kg from M.
leucadendron plantations with tree ages ranging from 21 to 43 years old, which were planted in plot 31 at Forest Management Unit (FMU) Yogyakarta or KPH Yogyakarta (Indonesi.
in Karangmojo district .
570 'S, 110.
400 'E).
Gunungkidul.
Indonesia.
The plant was identified by Mr.
Andi Nugroho based on compared to digital herbarium plants from the Royal Botanic Garden Kew.
The voucher number of the plant is K000793405.
Plot 31 contained a homogenous category Chemical Constituents of Melaleuca leucadendron Linn.
Leaf Essential Oils Quality .
(Rizki Arisandi et al.
based on remote sensing mapping.
The plots were selected randomly, and 9 plot experiments were obtained as representatives.
The leaves of leucadendron were taken in each experimental plot with a size of 20 x 20 m with nine replication measurements on the same trees every month.
In addition, to analyze the effect of seasonality on the essential oils of this species, the collection period was nine months, from August 2017 to April 2018.
Comprehensive data on field conditions and plot experimental selection were defined in parallel work (Mulyana.
Rohman, & Wardhana, 2018.
Mulyana.
Siallagan.
Yuwono, & Purwanto, 2.
During the collection period, higher rainfall was recorded in the months of November.
December.
January, and March (Table .
On the other hand, lower precipitation was observed during the months of August and September (Badan Pusat Statistik, 2.
Furthermore.
Meteorology.
Climatology, and Geophysical Agency (BMKG, 2.
also categorized the rainfall rate, namely 5 - 20 mm day-1 .
: light rain.
20-50 mm day-1 .
: moderate rain.
50 - 100 mm day1 .
: heavy rain.
100 - 150 mm day-1 .
very heavy rain.
Isolation of essential oils 15 kg of fresh leaves sample was isolated by water steam distillation in 3 of the plant chambers of a stainless-steel apparatus .
kg per plant chambe.
for 6 hours.
Each month, all distillations were carried out in triplicate, and the essential oils produced were purified from the remaining water using magnesium sulfate monohydrate (MgSO4.
H2O).
Then, the essential oil was stored in the vial at approximately 0AC prior to the GC-MS analysis.
Gas chromatography-mass spectrometry (GC-MS) analysis The chemical constituent was identified by Gas chromatography-mass spectrometry (GC-MS-QP 2010.
Shimadzu.
Japa.
under the following conditions: DB-1 capillary column .
m x 0.
25 mm I.
25 m.
GL Sciences.
Japa.
carrier gas He.
temperature 290AC.
oven initial temperature 70A C held for 5 min.
temperature 6AC per final temperature 285A C held for 20 min.
0 l of M.
leucadendron essential oil injection.
The transfer-line temperature was 200AC, and the split ratio used was 1:50.
Compounds were investigated by comparing experimental GCMS data with the NIST MS library (NIST 2.
, and their retention indices based on literature research (Davies, 1990.
Fall.
Ngom.
Sall.
Sembene, & Samb, 2017.
Pujiarti et , 2011, 2012.
Monzote et al.
, 2.
The relative area percentage of the essential oil constituents was expressed as a percentage obtained by a computer integrator based on Table 1.
Rainfall information on the collection period of M.
Year Month August September October November December January February March April Rainfall number of Rainfall Total Max Min Average Light rain Light rain Light rain Light rain Light rain Light rain Light rain Light rain Light rain Temperature (AC) Average (%) Source: Badan Pusat Statistik .
Indonesian Journal of Forestry Research Vol.
10 No.
October 2023, 195-205 the total ion chromatography (TIC) peak area, with corresponding response coefficients are considered one (Bardakci.
Servi, & Polatoglu.
Bugayong.
Cruz, & Padilla, 2019.
Jin.
Ai.
Qu.
Cui, & Wang, 2019.
Mohamed.
Mohafez.
Khalil, & Alhaider, 2019.
Niczad.
Sharafzadeh.
Alizadeh.
Amiri, & Bazrafshan.
Qu et al.
, 2.
RESULT AND DISCUSSION
Physical properties and yield of essential The physical traits, i.
, specific gravity, refractive index, and solubility in alcohol as well as essential oil yield, ranged from 0.
874 to 0.
461 to 1.
468, 1:1 to 1:7, and 0.
17 to 0.
respectively (Mulyana et al.
, 2.
In general, all parameters were qualified according to SNI .
(Badan Standardisasi Nasional, 2.
and ISO 4730 .
he International Organization for Standardization 4730, 2.
In our previous studies, the highest content of essential oil was investigated in March, while the lowest essential oil yield was obtained in August.
Although March and August are in the same category .
ight rai.
based on the BMKG category, they have different numbers of rainfall per day and total rainfall (Table .
From these rainfall data.
April to September is the lowest rainfall period, while October to March is the highest rainfall period.
leucadendron trees produced higher essential oil content during the month of March, indicating higher rainfall rates than in August, where rainfall was lowest.
Other species with the same family (Myrtacea.
, such as Leptospermum petersonii, had higher yields of essential oils in the rainy season compared to the dry season (Demuner et al.
, 2.
Pirzad.
Alyari.
Shakiba.
Zehtab-Salmasi, and Mohammadi .
reported that the content of essential oil from Matricaria chamomilla had a higher essential oil content under irrigation at 85% of field capacity compared with irrigation at 55%.
Castelo et al.
mentioned that the essential oil of Psidium myrsinites grown in Brazil had the highest essential oil content in the dry season (Jul.
Rathore et al.
also ISSN: 2355-7079/E-ISSN: 2406-8195 stated that in Rosmarinus officinalis, the levels of essential oil were greater in the autumn and summer seasons compared to the rainy season.
Similar findings with higher essential oil content were reported in Nectandra spp.
(Ferraz et al.
and Achillea fragrantissima (Forssk.
) Sch.
Bip.
(Elsharkawy & Nahed, 2.
during the autumn and summer season, respectively.
addition, the highest essential oil content of this result was also found at high humidity and low Kaul.
Rajesware.
Bhattacharya, and Singh .
reported that the essential oil of Rose-Scented Geraniums was positively correlated with rainfall and humidity but negatively correlated with temperature.
The same pattern was also found in the species of Mentha arvensis L.
piperascens Holmes and Melaleuca alternifolia under the influence of day temperature (Duriyaprapan.
Britten, & Basford.
Lemos.
Rocha.
Melo.
Visser, & Pinheiro.
In view of this condition, water supply is, therefore, a critical factor affecting the production of essential oil.
The desired rainfall is a maximum of <1500 mm year-1 (Sadono et , 2.
In general, although irrigation may still be necessary where rainfall is less than 1000 mm year-1, this species is relatively well adapted to dry climates (Kartikawati.
Nirsatmanto.
Rimbawanto.
Sumardi, & Prastyono, 2.
In addition, there appears to be a flowering stage in M.
leucadendron trees, which can also affect the yield of essential oils.
Corryanti and Sugito .
reported the flowering stage in M.
leucadendron trees starts from January to April.
Serralutzu et al.
reported that essential oil content was greater in the longer flowering period than in the short period in Rosmarinus The same result was also stated by Rathore et al.
in the same species.
Previous studies in different species have shown that the content of essential oils is higher in the flowering stages of Mentha longifolia.
As stated by Golparvar.
Hadipanah, and Mehrabi .
compared to the vegetative stage, the flowering stage is known to be the most effective time for essential oil extraction.
In addition.
Kofdis.
Chemical Constituents of Melaleuca leucadendron Linn.
Leaf Essential Oils Quality .
(Rizki Arisandi et al.
Bosabalidis, and Kokkini .
also indicated that the maximum yield of essential oil was found at the flowering stage.
It is known that many factors, such as season, temperature, humidity, reproductive stage, and species, can lead to qualitative and quantitative differences in the essential oils production.
On the other hand, the distinction between yields of essential oils may also be related to whether younger or older leaves have been collected.
Yuan et .
demonstrated that young leaves of Blumea balsamifera had the highest essential oil yield, followed by mature leaves and senescent Chemical composition of essential oils The GC-MS analysis detected nine essential oil samples with different collection times from August 2017 to April 2018 are shown (Table Thirteen compounds were found in M.
leucadendron leaves essential oil samples.
These studies clarified and explained the variations Table 2.
Chemical constituent of the M.
leucadendron leaves essential oils Sr.
Compound
RI*
Lit.
-Thujene -Pinene -Pinene -Myrcene p-Cymene D-Limonene 1,8-Cineole -Terpineol -Caryophyllene Aromadendrene Humulene -Bisabolol -Eudesmol Concentration (%) Aug Sep Oct Nov Dec Jan Feb Mar Apr Monoterpene Hydrocarbons Oxygenated Monoterpenes Sesquiterpene Hydrocarbons Oxygenated Sesquiterpenes Remarks:
- not detected * Calculated retention indices on a DB-1 column ** Reference retention indices based on the literature Sr.
No.
1-6 (Monoterpene Hydrocarbon.
Sr.
No.
7-8 (Oxygenated Monoterpene.
Sr.
No.
9-11 (Sesquiterpene Hydrocarbon.
Sr.
No.
12-13 (Oxygenated Sesquiterpene.
Indonesian Journal of Forestry Research Vol.
10 No.
October 2023, 195-205 in the quality of bioactive compounds and the bioactivity of essential oils of M.
leaves collected from different collecting months in KPH Yogyakarta.
These classes were monoterpene and sesquiterpene hydrocarbons and oxygenated forms .
onoterpene and Constituents of monoterpene hydrocarbons from these essential oils, such as -thujene, -pinene, -pinene, -myrcene, and D ( )-limonene, have been identified in previous studies in M.
Leucadendron (Fall et al.
Patramurti.
Amin.
Nastiti, & Hariono.
Monzote et al.
, 2020.
Pujiarti et al.
, 2011,
In addition, 1,8-cineole is the most abundant in these oils, with a value ranging 8% to 76.
Previous studies have also stated that 1,8-cineole was the major compound in M.
leucadendron leaves (Budiadi et , 2005.
Fall et al.
, 2017.
Patramurti et al.
, 2020.
Pujiarti et al.
, 2011, 2.
In addition, other primary components have also been detected in each sample, i.
D ( )-limonene .
40 to 12.
%), p-cymene .
53 to 12.
9%), and -terpineol .
98 to 9.
98%) (Table .
These main components, besides 1,8-cineole, were also observed in previous studies in M.
leucadendron (Fall et al.
, 2017.
Monzote et al.
Patramurti et al.
, 2020.
Pujiarti et al.
2011, 2.
Moreover, certain components of sesquiterpene hydrocarbon groups, i.
-caryophyllene, humulene, aromadendrene, have been found in previous studies in leucadendron (Pujiarti et al.
, 2011, 2.
ISSN: 2355-7079/E-ISSN: 2406-8195
Furthermore, -eudesmol was also detected in Leucadendron (Fall et al.
, 2017.
Monzote et , 2.
Some of the components detected in this result have been also mentioned in ISO 4730 .
However, the main constituent of terpinen-4-ol .
ea tree oi.
was not found.
This may be ISO 4730 .
based on the species of M.
alternifolia or M.
However, the -terpineol compound in this study was still detected in which terpinen-4-ol is an isomer of the terpineol compound.
Effect of different collecting time The chemical composition of M.
shows that the major compound groups in these samples were oxygenated monoterpenes .
1%) (Figure .
The second major group was found in monoterpene hydrocarbons .
4%),
39%) and oxygenated .
05%).
Monoterpene hydrocarbons increased from August to December after a slight decrease in September, with the highest constituents found in both D ( )-limonene and p-cymene during the highest rainfall condition, low temperature, and high humidity period (November and Decembe.
(Figure .
In addition, this class showed a fluctuating pattern, with the largest and smallest amounts reported in December .
and April .
0%), respectively.
Oxygenated monoterpenes differed significantly in each month, with the highest levels in January and Figure 1.
Chemical composition based on peak area percentage from M.
Chemical Constituents of Melaleuca leucadendron Linn.
Leaf Essential Oils Quality .
(Rizki Arisandi et al.
Figure 2.
Major constituentsAo variation of essential oil of M.
leucadendron leaves collected at different time April .
1%) relative to the lowest levels in November .
9%).
1,8-cineole and -terpineol were the main constituents of oxygenated monoterpenes.
The 1,8-cineole content increased steadily from the lowest amount in November .
%) to the highest amount .
0 %) in January .
ighest rainfal.
On the other hand, when comparing the lowest with the highest rainfall period, -terpineol was found to be higher in the dry season compared to the rainy season, especially in September .
98 %), with the smallest concentration in February .
55 %).
In addition, other major compounds have become significant components between the lowest and highest rainfall conditions, such as D ( )-limonene and p-cymene during the higher rainfall (November and Decembe.
and -terpineol during the lower rainfall period (Septembe.
Of the periods analyzed, the November and December periods with higher rainfall and humidity were the richest in volatile compounds such as p-cymene.
D ( )-limonene, and other monoterpene hydrocarbons (Table 2.
Figure These major compounds may have marked the flowering period of this species in those It starts in January, with the highest amount of 1.
8-cineole.
The presence of the volatile compound in the essential oil can be related to the protection of the plant from predators or as a defense mechanism against external conditions such as pathogens.
Castelo et al.
showed that p-cymene, -pinene, -terpineol, and myrcene were higher in the fruiting period of B.
salicifolius and P.
which serves as a major signal to protect against predators.
The highest concentration of 1,8-cineole was found during flowering (Januar.
, which seems to attract its natural pollinators, bees or small insects.
In previous studies.
Holopainen .
and Demuner et .
reported that major compounds such as citronella and -citronellol .
xygenated monoterpene.
of L.
Petersonii flowers attract pollinators and serve as a protecting mechanism to protect the reproductive organs and their germination cells against pathogens or damages caused by ozone.
From this study, it is believed that the secondary metabolite production by plants may be influenced by environmental factors such as seasonality rainfall, and these factors may affect the yield and chemical composition of essential oils Gobbo-Neto and Lopes .
and Ferraz et al.
On the other hand, climatic conditions can influence the enzymatic activity of certain plant species and then affect the certain secondary metabolites biosynthesis, including terpenic compounds (Barros.
Zambarda.
Heinzmann, & Mallmann, 2.
Zouari-Bouassida et al.
noted that the yield of most compounds in different species, such as Mentha longifolia leaves.
Indonesian Journal of Forestry Research Vol.
10 No.
October 2023, 195-205 was higher in the flowering stage .
of oxygenated monoterpenes such as pulegone, 1,8-cineole.
L-menthone, -pinene, -pinene, cis iso-pulegone, and piperitenone.
On the other hand, these results also revealed that the highest daily rainfall, especially in January, was the time with the highest concentration of 1,8-cineole, which is the most commercial compound of M.
A variety of biological and pharmacological properties were assigned to 1,8-cineole.
Usually, 1,8-cineole was used to treat both upper and lower airway diseases, such as bronchial asthma (Juergens et al.
, 2.
In addition, with respect to D ( )-limonene, p-cymene, and -terpineol, these compounds had great potential in the food, pharmaceutical, and cosmetic industries.
Jidong .
has shown that D ( )-limonene has been used as a food flavoring agent.
For many years.
D ( )-limonene has been used as a flavor and fragrance additive in food, beverage, and consumer products.
In addition.
Joglekar.
Panaskar, and Arvindekar .
mentioned that p-cymene is used to prevent cough and eliminate phlegm.
Additionally, this component is used as a flavoring agent and also in the production of fungicides and pesticides (Bonjardim et al.
, 2.
The last compound, -terpineol, has been investigated as a common fragrance ingredient used in perfumes, cosmetics, flavoring foods, and beverages (Khaleel.
Tabanca, & Buchbauer, 2.
In addition to the main compounds, significant amounts of -pinene, -pinene, and humulene were found (Table .
In general, -pinene, and -pinene were present in all rainy periods and high humidity, whereas in the lowest rainfall conditions, these compounds were absent.
On the other hand, the reverse pattern was found for the concentration of The results observed here differed from those reported by Demuner et al.
They found that in the dry season, especially in the case of -pinene and -pinene, they were significantly higher than in the rainy season in both L.
madidum and L.
In addition, this study also showed that ISSN: 2355-7079/E-ISSN: 2406-8195 monoterpene hydrocarbons predominated in the highest rainfall period, while sesquiterpene hydrocarbons were found to be greater in the lowest rainfall period (Figure .
In contrast.
Demuner et al.
showed that the concentration of monoterpene hydrocarbons of L.
madidum spp and L.
flavescens (Myrtaceae famil.
was the largest in the dry season, while sesquiterpenes hydrocarbons were greater in the rainy season.
Kaul et al.
reported -pinene and -pinene were positively correlated with relative humidity, whereas those compounds were negatively correlated with atmospheric temperature.
Conversely, citronellol, citronellyl formate, citronellyl tiglate and 2-phenylethyl tiglate correlated positively with atmosphere temperature and negatively with relative humidity.
It should be noted that although studies are conducted using the same species, the quantity and quality of essential oil production can vary depending on the genetic, soil, extraction and climatic characteristics of the region (Castelo et , 2012.
Yuan et al.
, 2.
However, this study only showed variations in chemical constituents over a period of nine months.
The patterns and comparisons between the highest and lowest rainfall periods are incomplete, especially during the lowest rainfall periods.
Further research in 12 months .
ne yea.
is therefore needed to observe a complete trend of variation and comparison, both in rainy and dry seasons, in order to obtain the best time for the harvesting of essential oils from M.
leucadendron leaves.
IV.
CONCLUSION
In conclusion, the results showed that weather conditions in March with higher rainfall, humidity, and flowering stage were favorable for the essential oil production and increased by the amounts of 1,8-cineole (Januar.
D ( )-limonene (Novembe.
and p-cymene (Decembe.
Although the number of essential oils decreased during the lowest rainfall condition, the plant collected during this season contained a higher concentration of -terpineol (Septembe.
In addition, -pinene.
Chemical Constituents of Melaleuca leucadendron Linn.
Leaf Essential Oils Quality .
(Rizki Arisandi et al.
-pinene, and humulene were markers of weather condition differences.
In general, -pinene and -pinene were found in the high precipitation period .
uring the rainy seaso.
, while humulene was only found in the low precipitation period .
uring the dry seaso.
Therefore, the knowledge of the impact of environmental factors, such as seasonal variation and rainfall, would significantly help producers to know and choose the best time for plant harvesting and production to obtain a high amount of the desired compounds for the pharmaceutical and food industries.
ACKNOWLEDGEMENT
The authors would like to thank KPH Yogyakarta for providing the sample of M.
leucadendron trees.
REFERENCES