Aktivitas Antioksidan Tanaman Garut Asal Berbagai Lokasi di Pulau Jawa serta Pertumbuhan dan Kandungan Asam Folat pada Naungan yang Berbeda

Abstract

Tanaman garut (Maranta arundinacea L.) merupakan salah satu tanaman tropis yang bisa menghasilkan umbi dengan kualitas pati dan karbohidrat yang tinggi, butiran tepung yang halus dan harganya mahal. Tanaman ini terdistribusi luas di kawasan tropis, termasuk di Indonesia. Umbi garut telah banyak dimanfaatkan oleh masyarakat sebagai obat herbal dan alternatif pengganti makanan pokok. Tanaman garut memiliki potensi dikembangkan sebagai pangan fungsional karena mengandung berbagai senyawa fitokimia yang bermanfaat bagi manusia. Namun, belum banyak petani yang membudidayakan garut secara intensif akibat pengetahuan terhadap tanaman dan cara budidaya ini masih terbatas. Selain itu, belum ada informasi terkait aksesi dan kondisi lingkungan yang optimum bagi pertumbuhan garut. Oleh karena itu, penelitian ini bertujuan mengeksplorasi aksesi garut yang ada di pulau Jawa serta menguji aktivitas antioksidannya, serta mengevaluasi karakter morfofisiologinya dan kandungan asam folat saat diberi intensitas naungan yang berbeda. Eksplorasi dilakukan di beberapa lokasi di pulau Jawa, meliputi Yogyakarta, Malang, Banjar dan Sragen. Setiap lokasi dipilih 3 aksesi sebagai perwakilan dan sebagian umbi dibawa menuju kebun percobaan di desa Cikarawang, Dramaga, Bogor. Setiap tanah pertanian dari asal aksesi garut disimpan dan dianalisis karakteristiknya terhadap tekstur dan pH, sedangkan umbi diamati terhadap aspek morfologi, proksimat, kandungan fitokimia dan aktivitas antioksidan. Data hasil pengamatan dianalisis menggunakan uji ANOVA (a = 5%), jika berbeda nyata dilanjutkan dengan uji DMRT pada selang kepercayaan 95%. Hasil eksplorasi di pulau Jawa ditemukan 12 aksesi garut yang masih digunakan dalam proses pertanian. Aksesi Malang ditemukan pada ketinggian > 445 mdpl, sedangkan aksesi lainnya ditemukan pada ketinggian < 150 mdpl. Karakteristik tanah setiap lokasi menunjukkan tekstur maupun pH yang mirip. Tekstur tanah setiap lokasi didominasi oleh debu dan liat dengan sedikit pasir sehingga bertekstur liat berlempung. pH alami tanah tergolong netral-basa dengan pH potensial yang menandakan terdapat sedikit ion H+ dan Al3+ dalam tanahnya. Umbi yang diperoleh juga menunjukkan perbedaan panjang dan diameter antar aksesi. Aksesi B12 memiliki panjang dan diameter umbi paling besar dibandingkan aksesi lainnya. Namun, hasil analisis kadar proksimat menunjukkan bahwa aksesi B12 masih memiliki kadari air > 10%, sedangkan aksesi lainnya memiliki kadar air < 10%. Kadar abu total seluruh aksesi < 9%, sedangkan nilai rendemennya tergolong rendah yaitu < 3%. Walaupun rendah, kandungan senyawa fitokimia dalam ekstrak kental umbi sangat beragam, meliputi alkaloid, tanin, flavonoid dan saponin. Disisi lain, hasil uji aktivitas antioksidan menunjukkan bahwa IC50 ekstrak umbi garut terbaik adalah aksesi B4 (IC50 = 163,16 ppm). Aktivitas tersebut masih tergolong rendah sehingga memerlukan perlakuan khusus untuk meningkatkan kandungan fitokimia dan kemampuannya sebagai agen antioksidan. Berdasarkan hal tersebut, aksesi B12 cocok digunakan sebagai bibit untuk memperoleh hasil panen yang tinggi, sedangkan aksesi B4 cocok digunakan sebagai bahan baku industri makanan ataupun kosmetik yang memerlukan senyawa antioksidan alami. Hasil penelitian tersebut belum bisa mengidentifikasi kondisi lingkungan yang cocok bagi pertumbuhan tanaman garut. Selain itu, dasar penentuan aksesi unggul tidak bisa dilakukan berdasarkan aktivitas antioksidan. Oleh sebab itu, perlu diadakan penelitian lebih lanjut untuk mengungkap aksesi unggul dan kondisi lingkungan terbaik bagi tanaman garut. Penggunaan naungan menjadi pilihan terbaik dalam memperoleh aksesi unggul dan kondisi lingkungan yang optimum. Tanaman garut tergolong toleran terhadap naungan sehingga mampu tumbuh dan memperoleh panen yang cukup baik. Selain itu, tanaman garut juga mengandung asam folat yang tinggi. Sekitar 84% kebutuhan harian asam folat bisa terpenuhi oleh umbinya. Belum ada informasi terkait hubungan pemberian naungan terhadap kadar asam folat pada tanaman garut. Selain itu, belum ada laporan terkait pengaruh intensitas naungan yang berbeda terhadap morfologi dan fisiologi tanaman garut. Oleh karena itu, penelitian ini bertujuan menganalisis respon morfologi dan fisiologi aksesi tanaman garut hasil eksplorasi terhadap pemberian intensitas naungan yang berbeda, serta mengevaluasi perlakuan tersebut terhadap kandungan asam folat. Penelitian ini menggunakan 13 aksesi garut (12 aksesi dari hasil eksplorasi dan 1 aksesi dari koleksi BB-Biogen). Seluruh aksesi ditanam pada kebun percobaan di desa Cikarawang, Dramaga, Bogor selama 10 bulan. Pengamatan morfologi dilakukan terhadap aspek tinggi tanaman, jumlah daun, jumlah anakan, panjang dan lebar daun, bobot kering tajuk dan akar, bobot segar umbi dan kandungan pati. Pengamatan fisiologi dilakukan terhadap laju fotosintesis, konduktansi stomata dan laju transpirasi. Pengamatan asam folat dilakukan secara kualitatif dan kuantitatif. Pengamatan dilakukan saat tanaman berumur 1, 2, 3, 5, 8 dan 10 bulan. Namun, pengamatan bobot kering tajuk dan akar, bobot segar umbi, kandungan pati dan asam folat dilakukan pada saat panen atau tanaman berumur 10 bulan. Hasil pengamatan tinggi tanaman menunjukkan adanya hambatan pada awal pertumbuhan akibat pemberian naungan 45% dan 50%. Namun setelah tanaman berumur 5 bulan, tanaman mengalami peningkatan signifikan dibandingkan perlakuan cahaya penuh. Jumlah daun juga menunjukkan pola yang sama dengan tinggi tanaman. Disisi lain, jumlah anakan menunjukkan bahwa perlakuan naungan 50% memberikan dampak positif dibandingkan perlakuan naungan 45%. Rata-rata jumlah daun, jumlah anakan, panjang dan lebar daun setiap aksesi menunjukkan perbedaan nyata. Aksesi B6 dan B7 menunjukkan nilai tertinggi, sedangkan aksesi B4 dan B13 menunjukkan nilai paling rendah diantara aksesi garut lainnya. Aksesi B11 menunjukkan bobot kering tajuk paling tinggi, sedangkan aksesi B3 menunjukkan sebaliknya. Hasil panen dipengaruhi oleh intensitas naungan yang berbeda serta jenis aksesinya. Aksesi B2 menunjukkan peningkatan signifikan pada bobot umbi sehubungan dengan peningkatan intensitas naungan, namun aksesi B12 tidak menunjukkan perbedaan signifikan antar perlakuan. Disisi lain, aksesi B10 dan B11 yang diberi perlakuan naungan 45% menunjukkan peningkatan kadar pati dibandingkan perlakuan cahaya penuh. Laju fotosintesis dipengaruhi oleh banyaknya cahaya yang diterima oleh tanaman. Hasil pengamatan menunjukkan bahwa laju fotosintesis pada tanaman yang ternaungi 45% dan 50% lebih tinggi dibandingkan tanaman yang diberi perlakuan cahaya penuh. Laju transpirasi pada perlakuan naungan 45% lebih tinggi dibanding perlakuan lainnya pada saat tanaman berumur 3-5 bulan. Konduktansi stomata menunjukkan bahwa tidak ada perbedaan nyata antar perlakuan, khususnya saat tanaman berumur lebih dari 3 bulan. Asam folat pada ekstrak umbi garut terkonfirmasi melalui lempengan kromatografi lapis tipis (KLT). Hasil pengujian menemukan adanya kemiripan nilai retardation factor (Rf) antara sampel dengan larutan standar. Rf2, Rf3, Rf5 dan Rf6 menjadi lokasi yang memiliki nilai mirip ataupun sama antara sampel dengan larutan standar. Namun, seluruh sampel menunjukkan kesamaan pada nilai Rf3. Hasil ini terkonfirmasi pada analisis kromatogtafi cair kinerja tinggi (KCKT) yang menunjukkan adanya kandungan asam folat pada umbi garut. Aksesi B2, B6, B12 dan B13 memiliki kandungan asam folat yang tinggi diantara aksesi lainnya. Selain itu, naungan 50% memberikan dampak paling signifikan terhadap peningkatan akumulasi asam folat. Aksesi B13 menunjukkan hambatan pertumbuhan pada saat tanaman diberikan naungan 45% maupun 50%, sedangkan aksesi B7 menunjukkan akumulasi asam folat yang rendah sehubungan dengan peningkatan intensitas naungan. Berdasarkan hal tersebut, aksesi B6 menjadi aksesi potensial dalam memperoleh asam folat yang tinggi dengan kondisi mofologi dan fisiologi yang baik. Selain itu, naungan 50% memberikan efek yang paling baik terhadap akumulasi asam folat pada umbi. Maka itu, kombinasi penggunaan aksesi B6 dengan naungan 50% diduga mampu menghasilkan panen dan kandungan asam folat terbaik pada budidaya garut. Berdasarkan hasil eksplorasi dan pengujian terhadap intensitas naungan yang berbeda. Aksesi B12 berpotensi dimanfaatkan dalam kegiatan pertanian garut, khususnya dalam memperoleh ukuran umbi yang besar. Di sisi lain, aksesi B6 menjadi aksesi unggul untuk memperoleh kadar pati dan asam folat yang tinggi, maka aksesi ini berpotensi dimanfaatkan sebagai sumber pangan fungsional.

Arrowroot (Maranta arundinacea L.) is a tropical plant known for producing tubers with high-quality starch and carbohydrate content, fine flour granules, and relatively high economic value. This plant is widely distributed across tropical regions, including Indonesia. Arrowroot tubers have long been utilized by local communities as herbal medicine and as an alternative staple food. Due to its content of various beneficial phytochemical compounds, arrowroot holds great potential to be developed as a functional food. However, its intensive cultivation remains limited, primarily due to a lack of knowledge about the plant and its agronomic practices. In addition, there is a lack of information regarding suitable accessions and optimal environmental conditions for arrowroot growth. Therefore, this study aims to explore the arrowroot accessions found on Java Island and to evaluate their responses to varying levels of shading intensity. The exploration was conducted in several locations across Java Island, including Yogyakarta, Malang, Banjar, and Sragen. Three accessions were selected from each location as representatives, and a portion of the tubers was brought to the experimental field located in Cikarawang Village, Dramaga, Bogor. The agricultural soil from each arrowroot accession's original site was collected and analyzed for its texture and pH characteristics. Meanwhile, the arrowroot tubers were evaluated for morphological traits, proximate composition, phytochemical content, and antioxidant activity. The observational data were analyzed using ANOVA (a = 5%), and when significant differences were detected, further analysis was conducted using the DMRT test at a 95% confidence interval. The exploration conducted on Java Island identified 12 arrowroot accessions that are still actively cultivated in agricultural practices. The Malang accession was found at an elevation of over 445 meters above sea level (masl), while the other accessions were located at elevations below 150 masl. Soil characteristics across all locations exhibited similar texture and pH profiles. The soil texture at each site was predominantly silty and clayey with minimal sand content, resulting in a clay loam texture. The natural soil pH ranged from neutral to slightly alkaline, while the potential pH indicated low concentrations of H? and Al³? ions in the soil. The harvested tubers also exhibited variations in length and diameter among the accessions. Accession B12 had the largest tuber length and diameter compared to the others. However, proximate analysis revealed that accession B12 still had a moisture content greater than 10%, whereas the other accessions had moisture contents below 10%. The total ash content of all accessions was below 9%, and the yield was relatively low, less than 3%. Despite the low yield, the concentrated tuber extracts contained a diverse range of phytochemicals, including alkaloids, tannins, flavonoids, and saponins. On the other hand, antioxidant activity assays showed that the best IC50 value was found in accession B4 (IC50 = 163,16 ppm). This level of activity is still considered low, indicating the need for specific treatments to enhance both the phytochemical content and the antioxidant potential of the tuber extracts. Based on these findings, accession B12 is suitable for use as seed material to achieve high yields, while accession B4 is more appropriate as a raw material for food or cosmetic industries that require natural antioxidant compounds. However, this study was not able to identify the optimal environmental conditions for arrowroot growth. Furthermore, the determination of superior accessions cannot be based solely on antioxidant activity. Therefore, further research is necessary to identify high-performing accessions and to determine the most favorable environmental conditions for the cultivation of arrowroot. The use of shading is considered a promising approach to identify superior accessions and determine optimal environmental conditions. Arrowroot is classified as a shade-tolerant plant, capable of growing and yielding satisfactorily under shaded environments. Moreover, arrowroot tubers are known to contain high levels of folic acid, with approximately 84% of the daily folate requirement potentially met by consuming their tubers. However, there is currently no information on the relationship between shading and folic acid content in arrowroot. In addition, no studies have reported the effects of varying shading intensities on the morphological and physiological characteristics of arrowroot. Therefore, this study aims to analyze the morphological and physiological responses of selected arrowroot accessions to different shading intensities, and to evaluate the impact of shading on folic acid content. This study utilized 13 arrowroot accessions—12 accessions obtained from field exploration and 1 accession from the BB-Biogen collection. All accessions were cultivated in an experimental field located in Cikarawang Village, Dramaga, Bogor, for 10 months. Morphological observations included plant height, number of leaves, number of tillers, leaf length and width, shoot and root dry weight, fresh tuber weight, and starch content. Physiological measurements included photosynthetic rate, stomatal conductance, and transpiration rate. Folic acid content was assessed both qualitatively and quantitatively. Observations were carried out at plant ages of 1, 2, 3, 5, 8, and 10 months. However, measurements of shoot and root dry weight, fresh tuber weight, starch content, and folic acid content were conducted only at harvest, i.e., at 10 months of age. Observations on plant height indicated initial growth inhibition under 45% and 50% shading treatments. However, after five months of growth, plants under these shading conditions showed a significant increase in height compared to those grown under full sunlight. The number of leaves followed a similar pattern to plant height. In contrast, the number of tillers indicated that 50% shading had a more positive impact compared to 45% shading. The average number of leaves, number of tillers, as well as leaf length and width showed significant differences among accessions. Accessions B6 and B7 exhibited the highest values, whereas accessions B4 and B13 recorded the lowest among all arrowroot accessions. Accession B11 exhibited the highest shoot dry weight, while accession B3 recorded the lowest. Harvest yield was influenced by both shading intensity and accession type. Accession B2 showed a significant increase in tuber weight with increasing shading intensity, whereas accession B12 showed no significant differences across treatments. On the other hand, accessions B10 and B11 under 45% shading exhibited higher starch content compared to those grown under full sunlight. The photosynthetic rate was influenced by the amount of light received by the plant. Observations showed that plants grown under 45% and 50% shading exhibited higher photosynthetic rates compared to those under full sunlight. Transpiration rate under 45% shading was higher than in other treatments, particularly during the 3 – 5 months growth period. Stomatal conductance did not show any significant differences among treatments, especially after the plants reached three months of age. Folic acid in the arrowroot tuber extracts was confirmed through thin-layer chromatography (TLC). The results showed similarities in the retardation factor (Rf) values between the samples and the standard solution. Rf2, Rf3, Rf5, and Rf6 were the positions where similar or identical values were observed between samples and the standard; notably, all samples consistently shared the same Rf3 value. These findings were further validated by HPLC analysis, which confirmed the presence of folic acid in the arrowroot tubers. Accessions B2, B6, B12, and B13 exhibited the highest folic acid content among all accessions. Additionally, the 50% shading treatment had the most significant effect in enhancing folic acid accumulation. Accession B13 exhibited growth inhibition under both 45% and 50% shading treatments, while accession B7 showed low folic acid accumulation in response to increased shading intensity. Based on these findings, accessions B6 is considered the most promising for achieving high folic acid content while maintaining favorable morphological and physiological characteristics. Moreover, the 50% shading treatment had the most pronounced effect in enhancing folic acid accumulation in the tubers. Therefore, the combination of accessions B6 with 50% shading is suggested to be the optimal strategy for maximizing both yield and folic acid content in arrowroot cultivation. Based on the results of exploration and testing under different shading intensities, accession B12 has potential for use in arrowroot cultivation, particularly for producing large tuber sizes. In contrast, accession B6 is considered a superior accession for obtaining high starch and folic acid contents, making it a promising source for functional food development.