Effect Of Betel Leaf Extract Research Articles

SYNTHESIS OF BIODEGRADABLE PLASTIC FROM (Artocarpus heterophyllus Lam), (Zea mays) AND (Piper betle) USING GLYCEROL AS PLASTICIZER

This study aims to produce starch-based bioplastic that is environmentally safe and reduces pollution. This research aims to investigate the effect of betel leaf extract as an antimicrobial agent on the characteristic of bioplastic based on jack fruit seed starch. Bioplastics are the only solution to replace plastics. As a result, these nonbiodegradable plastics remain in the environment for a long time and cause an increase in solid waste production. Starch is one of the major sources in the development of bioplastics. The bioplastic was produced from the starch of jackfruit seed along with glycerol as a plasticizer and analyzed for its physical and mechanical properties. The bioplastic produced was analysed for its antimicrobial activity. The produced bioplastic showed better physio mechanical properties and can be used widely in industries. Keywords: Bioplastics, Glycerol, Jackfruit, Cornleaf, Betel leaf.

Effectiveness of Betel Leaf Extract Against Cercospora sp. Pathogen Causing Chili Leaf Spot In-Vitro

The betel plant grows a lot and is easy to find in Indonesia. Part of the betel leaf contains antifungal compounds. This research examined the effect of betel leaf extract and its effective concentration in suppressing the pathogen Cercospora sp. in vitro. The research was conducted at the Pesticide Toxicology Laboratory, Universitas Brawijaya. Using a completely randomized design (CRD) with six treatments and five replications. The treatment was carried out in control and betel leaf extract with concentration levels of 30,000 ppm, 50,000 ppm, 100,000 ppm, 150,000 ppm, and 200,000 ppm. The results obtained were screening tests of compounds, causal tests of extracts on fungi, percentage of inhibition, and growth rate on fungi. Giving betel extract can suppress the growth of the fungus Cercospora sp., and in the 200,000 ppm extract treatment, the results were moderately effective in testing the percentage of inhibition power of the fungus Cercospora sp., which is equal to 41%.

Incorporation of betel leaf extract provides oxidative stability and improves phytochemical, textural, sensory and antimicrobial activities of buffalo meat sausages

The antioxidant effect of betel leaf extract (BLE) on lipid and protein oxidation, microbial count and physicochemical attributes was investigated in meat sausages during refrigerated storage at 4 ± 1 °C. Buffalo meat sausages were developed after incorporating 0, 250, 500 and 750 mg kg−1 of BLE (BLE0, BLE1, BLE2 and BLE3) respectively. The sausages showed no changes in proximate composition due to BLE inclusion, but there was an improvement in microbial quality, color score, textural properties and lipid and protein oxidative stability. Further, higher sensory scores were observed for the BLE-incorporated samples. The images from scanning electron microscopy (SEM) revealed a reduction in surface roughness and unevenness showing microstructure modification in BLE treated sausages compared to the control sausages. Hence, to improve the storage stability and impede the rate of lipid oxidation in sausages, BLE incorporation proved to be an effective strategy.

EFFECT OF BETEL LEAF EXTRACT (Piper betle L.) ON Aeromonas hydrophila DISEASES IN TILAPIA (Oreochromis niloticus) SEED

Seed is essential in aquaculture activities, but tilapia hatcheries often suffer from disease attacks caused by Aeromonas hydrophila bacteria, causing losses for hatchery businesses. One of the natural ingredients for treating Aeromonas hydrophila is betel leaf extract. This study aims to analyze the effect of betel leaf extract (Piper betle L.) on Aeromonas disease hydrophila on fish fry tilapia (Piper betle L.). This study used a completely randomized design (CRD) with 5 treatments and 3 replications. The treatment used was a dose of betel leaf extract (P1) 0.4 ml, (P2) 0.6 ml, (P3) 0.8 ml, (P4) positive control, (P5) negative control. The parameters observed were survival rate, specific growth rate, feed conversion ratio, absolute length growth, erythrocytes, hemoglobin, hematocrit, leukocytes, differential leukocytes, total bacteria count, and water quality. The results of this study showed that before and after the challenge test, the best average values were P3 leukocytes (1.06 and 1.4 x 10 5 ), erythrocytes (0.90 and 0.93 x 10 5 ), hemoglobin (10.9 and 9.7), hematocrit (10.7 and 10.3), total bacteria (7 x 10 1 ). Then the worst value on P1 leukocytes (0.74 and 0.87 x 10 5), erythrocytes (0.86 and 0.75 x 10 5 ), hemoglobin (10.7 and 7.7), hematocrit (10.3 and 9.3), total bacteria (74 x 10 2 ). The study concluded that the best treatment was found in treatment 3 with a dose of 0.8 ml of betel leaf extract, which significantly increased the immune system in tilapia seeds.

Betel Leaf Extract’s Effect (Piper Batle Linn) on The Healing Process of Incision Wounds in Rats (Rattus Norvegicus)

An incision wound is a wound that is intentionally made by a clean-cut using a sharp object. Betel leaf is a natural ingredient that helps the wound healing process because it has active ingredients such as saponins, tannins, flavonoids, essential oils, and alkaloids. The study aimed to determine the effect of betel leaf extract on the healing process of incision wounds in white rats. This study uses a true experimental research design conducted on white rats. Samples were taken by random sampling and divided into four groups, namely control group (KK) (n = 6), treatment group with a dose of 10% (P1) (n = 6), treatment group with a dose of 15% (P2) (n = 6) and treatment group with a dose of 20% (P3) ( n = 6). The mean of wound’s length in KK=0.78 cm, P1=0.67 cm, P2=0.57 cm, and P3=0.15. Based on the Kruskal Wallis test, p value=0.000(α0.05), there is a significant difference in the wound healing process between the control and treatment groups. Betel leaf contains active substances, namely flavonoids, alkaloids, saponins, tannins, and essential oils. The active substance causes the wound’s edges to close faster, so the wound heals faster.

The Effect of Betel Leaf Extract on The Growth of Colletotrichum capsici in Red Chili

Abstrak Tanaman cabai merupakan jenis sayuran penting yang banyak dibutuhkan oleh masyarakat. Namun, berdasarkan data Badan Pusat Statistik menunjukkan bahwa produksi cabai mengalami penurunan yang salah satunya disebabkan oleh Colletotrichum capsici. Penelitian ini bertujuan untuk mengetahui pengaruh pemberian ekstrak daun sirih terhadap pertumbuhan C. capsici. Penelitian ini dilakukan menggunakan Rancangan Acak Lengkap (RAL) dengan 3 kali pengulangan. Proses ekstraksi daun sirih dilakukan dengan metode maserasi dengan pelarut etanol 96% dan uji antifungi dilakukan dengan metode difusi Kirby-Bauer. Konsentrasi ekstrak daun sirih yang digunakan adalah 5%, 10%, 15%, 20%, dan kontrol negatif menggunakan dimetil sulfoksida (DMSO). Data yang diperoleh dianalisis secara statistik menggunakan uji One-Way Anova dan uji lanjut Least Significant Difference (LSD). Hasil penelitian ini menunjukkan bahwa konsentrasi ekstrak daun sirih 20% menghasilkan zona hambat terbesar, yaitu 0,84 mm. Berdasarkan hasil pengujian disimpulkan bahwa ekstrak daun sirih memiliki aktivitas antifungi dalam menekan pertumbuhan C. capsici.AbstractChili plants are important vegetables normally used by the community. However, based on the data of Badan Pusat Statistik, chili production is decreasing because of many factors, including Colletotrichum capsici pathogen. This study was aimed to determine the effect of betel leaf extract on the growth of C. capsici. This research was conducted using a completely randomized design with 3 replications. The extraction process was carried out by the maceration method with 96% ethanol solvent and the antifungal test was performed by the Kirby-Bauer diffusion method. The concentration of betel leaf extract used was 5%, 10%, 15%, 20%, and dimethyl sulfoxide (DMSO) was used as the negative control. The data obtained were analyzed statistically using the One-Way Anova test and the Least Significant Difference (LSD) posthoc test. The results of this study showed that the concentration of 20% betel leaf extract produced the largest inhibition zone of 0.84 mm. Based on the test results, it is concluded that betel leaf extract had antifungal activity in suppressing the growth of C. capsici.

The Effect of Betel (piper betle) leaf extract as antimicrobial agent on characteristics of bioplastic based on sago starch

Betel leaf extract contains many phenolic compound such as tannin and flavonoid which have antibacterial and antifungal properties. This study aims to investigate the effect of betel leaf extract addition in bioplastic based on sago starch (Metroxylon sp.) which includes density, water absorption, functional group characterization and antimicrobial activity. The betel leaf was extracted by using the ultrasonication method with ethanol as a solvent. Then betel leaf concentrated extract is diluted using aquadest with a concentration of 2 g/100 mL (2%) to be applied as an antimicrobial agent in bioplastics. The compositions of betel leaf extract as antimicrobials were varied in bioplastics making. The results show the highest density was 1.448 g/cm3 indicated by the variation of 9% betel leaf extract. The highest water absorption percentage was shown by sample without betel leaf extract addition (0% betel leaf extract), which was 75.56%. The antibacterial activity showed that the addition of betel leaf extract to bioplastics was able to inhibit the activity of bacteria (Bacillus cereus). The best inhibition were shown in bioplastics with a variation with 9% betel leaf extract addition. However, all variation did not show their inhibition with fungal activity (Aspergillus niger).

UTILIZATION OF BETEL LEAVES EXTRACT TO PREVENT THE GROWTH OF Fusarium oxysporum f.sp. capsici CAUSING FUSARIUM WILT DISEASE IN BELL PEPPER

Betel (Piper betle Linn.) is commonly used in Indonesian traditional medicine due to its antimicrobial properties, thus it is often used as an ingredient in natural pesticides. The effectiveness of betel leaf extract as a control for Fusarium oxysporum in several plants showed it’s potential to control the fungi in bell pepper. F. oxysporum f.sp. capsici is one of the important pathogens causing Fusarium wilt disease in bell pepper. It is one of the most devastating plant diseases due to its ability to cause a crop failure. The test on the inhibitory capacity of betel leaf extract on the growth of F. oxysporum f.sp. capsici were carried out by growing the fungi on PDA mixed with various concentrations of betel leaf extracts. The results showed that betel leaf extract treatment at 0.02% concentration was able to inhibit the growth of F. oxysporum f.sp. capsici in PDA at 95.54%. The full inhibition of colony growth (100%) was achieved in the extract treated with the concentration of 0.03%. Meanwhile treatment of 0.17% betel leaf extract was able to inhibit the growth of F. oxysporum f.sp. capsici on bell pepper stems. Following this result, fractionation of the betel leaf extract by column chromatography was conducted, resulting in 44 fractions. The bioassays of those fractions showed that, there were seven fractions that reveal inhibition capability against F. oxysporum f.sp. capsici.

UTILIZATION OF BETEL LEAVES EXTRACT TO PREVENT THE GROWTH OF Fusarium oxysporum f.sp. capsici 1 CAUSING FUSARIUM WILT DISEASE IN BELL PEPPER

Utilization of betel leaves extract to prevent the growth of Fusarium oxysporum f.sp. capsici causing fusarium wilt diseasein bell pepper. Betel (Piper betle Linn.) is commonly used in Indonesian traditional medicine due to its antimicrobial properties,thus it is often used as an ingredient in natural pesticides. The effectiveness of betel leaf extract as a control for Fusariumoxysporum in several plants showed it’s potential to control the fungi in bell pepper. F. oxysporum f.sp. capsici is one of theimportant pathogens causing Fusarium wilt disease in bell pepper. It is one of the most devastating plant diseases due to itsability to cause a crop failure. The test on the inhibitory capacity of betel leaf extract on the growth of F. oxysporum f.sp.capsici were carried out by growing the fungi on PDA mixed with various concentrations of betel leaf extracts. The resultsshowed that betel leaf extract treatment at 0.02% concentration was able to inhibit the growth of F. oxysporum f.sp. capsici inPDA at 95.54%. The full inhibition of colony growth (100%) was achieved in the extract treated with the concentration of0.03%. Meanwhile treatment of 0.17% betel leaf extract was able to inhibit the growth of F. oxysporum f.sp. capsici on bellpepper stems. Following this result, fractionation of the betel leaf extract by column chromatography was conducted, resultingin 44 fractions. The bioassays of those fractions showed that, there were seven fractions that reveal inhibition capabilityagainst F. oxysporum f.sp. capsici.

THE EFFECTIVENESS TEST OF BETEL LEAF EXTRACT TOWARD THE DEVELOPMENT OF AEDES AEGYPTI SP LARVAE

This research was conducted to determine the effectiveness of betel leaf extract conducted at a concentration of 2.5%, 5.0%, 7.5%, 10% as larvicide toward the development of Aedes Aegypti Sp. Aedes Aegypti Sp larvae are dangerous vectors in Dengue Hemorrhagic Fever (DHF) in humans. The method in this research was carried out on an experimental method by using a post-test only design and sampling with a purposive sampling method. The effectiveness of betel leaf extract larvicide on the development of Aedes Aegypti Sp larvae was carried out by mixing betel leaf extract with several concentrations in one container Aedes Aegypti Sp larvae inside. The results obtained in this research were carried out by the Kruskal-Wallis test, the test found that there was a significant difference because it was given a 95% confidence index. The larvae treated with betel leaf extract with a concentration of 10% had the highest effectiveness in stopping the development of Aedes Aegypti Sp larvae, which proved at the mortality at a concentration of 10%, found total mortality of 20 larvae in 8 hours of treatment. Betel leaf extract with a concentration of 10% had the highest effectiveness of discontinuing the development of Aedes Aegypti Sp larvae.

EFEKTIVITAS EKSTRAK DAUN SIRIH SEBAGAI BAHAN AKTIF ANTIBAKTERI DALAM GEL HAND SANITIZER NON-ALKOHOL

<p><strong>Abstrak</strong><strong>. </strong>Penelitian ini bertujuan untuk mempelajari efektivitas ekstrak daun sirih sebagai pengganti bahan aktif antibakteri pada hand sanitizer. Ekstrak daun sirih diperoleh dengan cara maserasi daun sirih selama 3x24 jam dalam larutan alkohol 70%. Kadar alkohol pada ekstrak daun sirih hasil maserasi diuapkan dalam vacuum evaporator (T = 60<sup>o</sup>C) hingga volume ekstrak yang tersisa sekitar 15%. Ekstrak ini digunakan sebagai bahan antibakteri aktif dalam pembuatan gel pembersih tangan. Bahan kimia dasar pembuatan gel seperti karbomer (zat pembentuk gel), propilen glikol (penstabil), gliserin, nipagin dan trietanolamina / TEA (zat alkali) dicampur dan diaduk dalam air suling (sekitar 85 ml) dengan komposisi 0,3 g, 4 ml, 3 ml, 0,02 g dan 0,2 ml, masing-masing. Volume ekstrak yang ditambahkan ke dalam gel divariasikan 8, 10, dan 12 ml. Terakhir, volume hand sanitizer ditambahkan aquades untuk mengatur volumenya 100 ml. Efektivitas dan kualitas hand sanitizer ini dianalisis senyawa aktifnya, keasaman gel (pH), organoleptik, daya hambat pertumbuhan bakteri, dan dispersi gel. Staphylococcus aureus dipilih sebagai bakteri yang diuji karena ditemukan di tangan. Kehadiran saponin, tanin, dan flavonoid terdeteksi secara kualitatif di dalam produk. Hasil penelitian menunjukkan bahwa penambahan ekstrak daun sirih 12 ml (sampel III) memiliki kinerja terbaik pada kisaran konsentrasi ekstrak yang diteliti (8-12 ml). Sampel III memiliki keasaman (pH) dan zona hambat masing-masing sekitar 5 dan 9,78 mm2. Area hambat ini lebih tinggi dibandingkan dengan hand sanitizer komersial yang memiliki luas 2,98 mm2. Namun, daya sebar hand sanitizer ini sedikit lebih rendah dibandingkan hand sanitizer komersial (sekitar 167% dan 180%). Uji organoleptik menggambarkan bahwa produk ini dapat diterima di masyarakat karena tidak mengiritasi dalam pemakaian. Produk ini lebih aman sebagai hand sanitizer dibandingkan produk sejenis yang menggunakan alkohol sebagai bahan aktifnya.</p><p><strong> </strong></p><p><strong>Abstract.</strong> This research aims to study the effectiveness of betel leaf extract as a substitute for antibacterial active ingredients in hand sanitizer. Betel leaf extract is obtained by maceration of betel leaves for 3x24 hours in 70% alcohol solution. The alcohol content in the betel leaf extract from maceration was evaporated in the vacuum evaporator (T = 60<sup>o</sup>C) until the remaining extract volume was around 15%. This extract is used as an active antibacterial ingredient in making hand sanitizer gel. The basic chemicals of making gels such as carbomer (gelling agent), propylene glycol (stabilizer), glycerin, nipagin and triethanolamine / TEA (alkalizing agent) are mixed and stirred in distilled water (about 85 ml) with compositions of 0.3 g, 4 ml, 3 ml, 0.02 g and 0,2 ml, respectively. The volume of extract added in the gel was varied 8, 10, and 12 ml. Finally, the volume of hand sanitizer was added distilled water to adjust its volume 100 ml. The effectiveness and quality of this hand sanitizer were analyzed its active compounds, gel acidity (pH), organoleptic, the inhibitory ability of bacterial growth, and gel dispersion. <em>Staphylococcus aureus</em> was chosen as the bacteria tested because it found in the hands. The presence of saponin, tannins, and flavonoids is detected qualitatively in the product. The results showed that adding 12 ml extract of betel leaf (sample III) has the best performance in the studied range of extract concentration (8-12 ml). Sample III has the acidity (pH) and the inhibitory zone about 5 and 9.78 mm<sup>2</sup>, respectively. This inhibitory area is higher than that of the commercial hand sanitizer, which has an area of 2.98 mm<sup>2</sup>. However, the spreadability of this hand sanitizer is slightly lower than that of the commercial one (about 167% and 180%). Organoleptic tests depict that this product is acceptable in the community because it does not irritate in use. This product is safer as hand sanitizer than the similar products that use alcohol as an active ingredient.<strong></strong></p><p><strong>Keywords </strong>: betel leaf, antibacterial, hand sanitizer, Staphylococcus aureus</p>

IDENTIFICATION OF ANTHRACHNOSE DISEASE ON STRAWBERRY FRUIT (Fragraria vesca L.) AND ITS CONTROL BY BETEL (Piper betle L.) LEAF EXTRACT

<p>In Indonesia, strawberry is one of fruits which has high economic values. The growth of strawberry has increased significantly, but its productivity is still low because of disease attack. Disease that attacks strawberry started from nursery to post harvest is anthracnose that can be caused by Colletotrichum spp. Control efforts of anthracnose disease up to now has been done with application of synthetic chemicals which are known to be hazardous to the environment and human health. Betel leaf (Piper betle L.) is natural plant that potentially used as phytofungicide. Essential oils on betel leaf extract is reported can decrease the growth of pathogenic fungi. The objectives of the research were to identify Colletotrichum spp. in strawberry fruit that showed anthracnose symptoms, to test the potency of betel leaf extract as phytofungicide, and to evaluate the effect of betel leaf extract in inhibiting infection and disease severity of Colletotrichum in strawberry. Samples were taken from strawberry nursery in Magelang, Indonesia. The disease symptoms were isolated on Potato Dextrose Agar, followed by identification of fungal colony and morphology by semi permanent slide preparation. Betel leaves were extracted with water to get a concentration of 20, 40, 60, 80 and 100%, respectively. An in vitro experiment was done to evaluate the inhibition rate of betel leaf extract to the growth of Colletotrichum spp. colony. An in vivo experiment was done by submersion of strawberry to betel leaf extract before (preventive method) and after antrachnose attack (curative method), then disease infection and disease severity were measured after 7 days. The result of the research showed that anthracnose disease in strawberry was caused by C. gloeosporioides (Penz.). Twenty percent of betel leaf extract in an in vitro test had potential as phytofungicide and concentration of 100% betel leaf extract was the best concentration to inhibit the growth of C. gloeosporioides (Penz.) colony by 70.26±0,61%. In an in vivo experiment, submersion of strawberry before pathogen infection (preventive) with 100% betel leaf extract decreased disease infection by 40% and disease severity by 16%, respectively. While treatment of submersion of strawberry after pathogen infection (curative) decreased disease infection by 33,4% and disease severity by 17%. </p><p>Keywords: strawberry, anthrachnose, disease, betel leaf</p>

Effect of Betel Leaf Extract on Nerve Impulse Conduction through Sciatic Nerve in Frog Using a Modified Technique

Plain betel leaf extract is reported to produce local anesthesia by surface and infiltration techniques. Objective : (1) to explore the effect of betel leaf extract on conduction of nerve impulse and (2) to evaluate its potency as compared to 2% xylocaine. Materials & Methods : The extract (12 to 15 ml) was prepared by squeezing ground betel leaf paste. An in situ gastrocnemius-sciatic nerve preparation was made on both the legs of a pithed frog and necessary electrical and kymograph connections were made. Xylocaine or betel leaf extract (0.2 ml) was applied on the sciatic nerve of one side and the other side served as control. The response to the electrical stimulus given proximal to the site of application alternatively on both sides was recorded on the same drum, until there was no response. Then the drug was washed off and recovery recorded. Results : Betel leaf extract produced statistically significant conduction block anesthesia of slow onset (25 min as against 2 min with xylocaine) and fast recovery (2 min as against 44 min with xylocaine) . The extract was found to possess 25% of the local anesthetic activity of xylocaine. Conclusions : Betel leaf extract produced a conduction block anesthesia of slow onset and quick recovery. It is less potent than xylocaine in this regard.

Protective single/combined treatment with betel leaf and turmeric against methyl (acetoxymethyl) nitrosamine-induced hamster oral carcinogenesis.

The inhibitory effect of oral administration of betel-leaf extract (BLE) and 2 of its constituents, beta-carotene and alpha-tocopherol, as single agents or in combination with dietary turmeric on methyl(acetoxymethyl)nitrosamine (DMN-OAC)-induced oral carcinogenesis in Syrian hamsters was studied. DMN-OAC was administered twice monthly for 6 months. The chemopreventive effect of BLE or its constituents with turmeric was determined by comparing tumor incidence observed in treated groups with that seen in control animals. The apparent site-specific chemopreventive effect of BLE or its constituents was demonstrated by inhibition of tumor incidence, reduction of tumor burden, extension of the tumor latency period and regression of established, frank tumors. The inhibitory effect of BLE or its constituents combined with turmeric was higher than that of the individual constituents. The study suggests that BLE could be developed as a potential chemopreventive agent for human oral cancer.

Chemopreventive efficacy of a betel leaf extract against benzo[ a]pyrene-induced forestomach tumors in mice

The effect of betel leaf extract and some of its constituents, eugenol, hydroxychavicol, β-carotene and α-tocopherol, on benzo[ a]pyrene-induced foestomach neoplasia in male Swiss mice was examined. Betel leaf and its constituents decreased the number of papillomas per animal with the maximum protection, considering molar dosage, exhibited by β-carotene and α-tocopherol. Except for β-carotene, eugenol, hydroxychavicol and α-tocopherol increased the levels of reduced glutathione in the liver while glutathione S-transferase activity was enhanced by all except eugenol. Of seven sources, Banarasi betel leaves showed the maximum amounts of β-carotene and α-tocopherol.

Anticarcinogenic effect of betel leaf extract against tobacco carcinogens

Epidemiological studies have implicated that betel quid offers some protection to tobacco induced carcinogenesis. Earlier studies in our laboratory have shown betel leaf extract (BLE) to be antimutagenic against standard mutagens and tobacco-specific N′-nitrosamines (TSNA), N′-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). In the present study, we have tested the anti-carcinogenic effect of BLE using Swiss male mice. Two protocols of study were used to test this effect. In the first protocol, the effect of BLE was tested against the standard carcinogen benzo[a]pyrene (BP) using Wattenberg's stomach tumor model, Cancer Res., 41 (1981) 2820–2823. In this protocol, BLE inhibited the tumorigenicity of BP to a significant extent. In the second protocol, the effect of BLE against the two tobacco-specific nitrosamines, NNN and NNK was studied using long-term studies on Swiss male mice. The nitrosamines were administered on the tongues of the mice, while the BLE was supplied in drinking water. Two doses of NNN (22 mg and 72 mg) and one dose of NNK (22 mg) were used. In this study, it was observed that the number of tumor bearing animals decreased, but the difference was significant only in the group treated with the low dose of NNN in combination with BLE. However, in all the BLE treated animals, irrespective of the dose of nitrosamine, the hepatic vitamin A and C levels were elevated significantly as compared to the corresponding nitrosaminetreated controls. These results indicate that BLE has a promising anticarcinogenic role to play in tobacco induced cancer.